Standard 621 - Obstruction Marking and Lighting - Canadian Aviation Regulations (CARs)

Last amendment to standard: 2021/11/02

Table of contents

• Amendment Foreword
• List of Figures

• Chapter 1 - Introduction
• Chapter 2 - General
• Chapter 3 - Marking and Markers, General (effective 2016/03/01)
• Chapter 4 - Lighting, General
• Chapter 5 - Red Obstruction Lighting System, Configuration "A"
• Chapter 6 - Medium Intensity White System, Configuration "D" (effective 2016/03/01)
• Chapter 7 - High Intensity White System, Configuration "B" and "C" (effective 2016/03/01)
• Chapter 8 - Dual Red/White Medium Intensity System, Configuration "E" (effective 2016/03/01)
• Chapter 9 - Dual Red/White High Intensity System, Configuration "F" (effective 2016/03/01)
• Chapter 10 - Marking and Lighting of Catenaries
• Chapter 11 - Marking and Lighting of Tethered Objects (effective 2016/03/01)
• Chapter 12 - Marking and Lighting of Wind turbines and Wind farms (effective 2016/03/01)
• Chapter 13 - Obstruction Lighting Characteristics
• Chapter 14 - Maintenance
• Chapter 15 - Aircraft Detection System (ADS)
• Chapter 16 - Light Intensity Reduction (LIR) System (effective 2021/08/06)
• Appendix A - Contact Information
• Appendix B - Specification for Obstruction Lighting Equipment
• Appendix C - Aeronautical Assessment Form for Obstruction Marking and Lighting

Amendment Foreword

• 1. Purpose. The purpose of this publication is to provide standards for marking and lighting of objects that present a hazard to the safe operation of aircraft.
• 2. Effective date. The requirements of this edition are effective 30 days after the date of publication.
• 3. Cancellation. Standard 621, Obstruction Marking and Lighting, 1st Edition, dated 31 December 2011 is cancelled by this publication.
• 4. Standards changes and existing facilities. Unless otherwise directed by the Minister, existing installations of marking and/or lighting do not need to be upgraded if installed prior to the effective date of this 2nd edition, with the exception of installations as indicated in section 601.26 of the Canadian Aviation Regulations (CARs) for which there is an external change [e.g. removal of a shielding object or air traffic pattern].
• 5. Application. In accordance with section 601.24 of the CARs, persons having responsibility for or control over a building or object that constitutes an obstacle to air navigation shall either mark and light the building, structure or object in accordance with the requirements of Standard 621, or use equivalent marking and lighting approved by the Minister.

List of figures

• Figure 2-1: Adjacent Structures
• Figure 2-2: Shielding of Cable Spans
• Figure 3-1: Day Marking - Checkerboard Pattern
• Figure 3-2: Day Marking - Banded Pattern
• Figure 3-3: Storage Tank Marking
• Figure 4-1: Configurations of Lighting on Skeletal Structures
• Figure 4-2: Methods of Monitoring
• Figure 5-1: Configuration A: Red Lighting Installation
• Figure 5-2: CL-810 and CL-864 Lights on Towers
• Figure 5-3: Alternative Configuration A' - Lighting Reduction to Reduce Bird Fatalities
• Figure 5-4: Prominent Buildings Lighting
• Figure 5-5: Bridge Lighting
• Figure 5-6: Groups of Objects
• Figure 6-1: Configuration "D": Medium Intensity White Flashing Lighting System
• Figure 7-1: Adjacent Building
• Figure 7-2: Lighting Adjacent Structures
• Figure 7-3: Lighting Adjacent Structures
• Figure 7-4: Configuration "B" and "C": High Intensity White Flashing System
• Figure 7-5: Hyperbolic Cooling Tower
• Figure 10-1: Catenary Markers
• Figure 10-2: Catenary Wire Lights
• Figure 10-3: Catenary Flashing Lights
• Figure 10-4: Catenary Configurations
• Figure 10-5: Catenary Flashing Lights with ADS
• Figure 12-1: Lighting Wind turbines; Heights up to 150 m AGL
• Figure 12-2: Lighting Wind turbines; Heights 150 m to 315 m
• Figure 12-3: MET Tower Marking
• Figure 13-1: Photocell Settings
• Figure 13-2: Low Intensity Photometric Requirement
• Figure 13-3: High and Medium Intensity Flashing Photometric Requirement
• Figure 14-1: In-service Aviation Orange Colour Tolerance Chart
• Figure 15-1: Catenary Crossing - Plan View
• Figure 15-2: Catenary Crossing - Profile View
• Figure 15-3: Potential Turning/Descent Manoeuvres

Chapter 1 Introduction

1.1 Definitions

In this Standard:

"appurtenance" - (Note: this term is defined as "projection" in the CARs) means that part of any vertical mast, pole or other appendage added to a building, structure or object that protrudes above the top of the building, structure or object; (accessoire)

"aviation colours" - for lighting, the colours as defined in the ICAO Annex 14; (couleurs)

"beam spread" - means the angle between the two directions in the vertical or horizontal plane in which the intensity is equal to 50 percent of the minimum specified peak beam effective intensity; (angle d'ouverture du faisceau)

"catenary" - means the curved span of overhead wires hung freely between two supporting structures, normally with regard to exceptionally long elevated spans over canyons, rivers and deep valleys; (caténaire)

"effective intensity" - means the effective intensity of a flashing light is equal to the intensity of a steady-burning (fixed) light of the same colour which produces the same visual range under identical conditions of observation; (intensité efficace).

"fixed light" - means a light having constant luminous intensity when observed from a fixed point; (feu fixe)

"lighting" - means any light displayed on an obstruction as a means of indicating the presence of the obstruction to pilots; (éclairage)

"lighting terms" - (unités photométriques)

• (a) Lumen - International System unit of luminous flux equal to the amount of light given out through a solid angle of 1 steradian by a point source of 1 candela intensity radiating uniformly in all directions. The unit expresses the quantity of light output per second. (lumen)
• (b) Candela - International System unit of luminous intensity of light emitted from a light source; equal to 1/60 of the luminous intensity per square centimetre of a blackbody radiating at the temperature of solidification of platinum (2,046° degrees Kelvin). A luminous intensity of one candela is one lumen per steradian (solid angle). The unit expresses the intensity of light within an incremental segment of the beam. (candela)
  (effective 2016/03/01)
• (c) Lux - International System unit of illumination, equal to one lumen per square metre (lm/m²). The unit expresses the amount of light falling on the surface area. (lux)

"marker" - means an object displayed on an obstruction during daytime as a means of indicating the presence of relatively invisible obstructions such as power lines; (balise)

"marking" - means a symbol, group of symbols, or markers that are displayed on the surface of an obstruction and intended to reduce hazards to aircraft by indicating the presence of the obstruction by day; (balisage)

"meteorological visibility" - means the greatest distance, expressed in statute miles, that selected objects (visibility markers) or lights of moderate intensity at night (25 candela) can be seen and identified under specific conditions of observation; (visibilité météorologique)

"painting" - means a marking applied to the surface of an obstruction and intended to identify the presence of the obstruction by day; (marque de peinture)

"vertical aiming angle" - means the angle formed between the horizontal and a line through the centre of the vertical beam spread. (calage en site)

"wind turbine" means a structure intended for the production of electrical power; comprising a support mast on which is installed a nacelle containing a generator unit and which supports rotor blades that are caused to rotate by the wind. The total height of the obstruction is the height of the nacelle, above ground level (AGL), plus the length of one of the blades held in a vertical position.(éolienne)

"wind farm" means a grouping of 3 or more wind turbines. (parc d'éoliennes)

"wind farm indicators" means light units installed with specified spacing on selected wind turbines and serving to indicate the location of a wind farm to pilots. (indicateurs de parc d'éoliennes)

1.2 Abbreviations and Symbols Used in this Standard
(effective 2016/03/01)

AGL

Above Ground Level

cd

candela (light intensity)

km/h

kilometres per hour

m

metre

kt

knot

FAA

Federal Aviation Administration

cm

centimetre

ft

foot

ICAO

International Civil Aviation Organization

max

maximum

min

minimum

ADS

Aircraft Detection System

FIC

Flight Information Centre

< x

less than x

> x

more than x

≥ x

equal to or more than x

≤ x

equal to or less than x

Chapter 2 - General

2.1 Purpose of Marking and Lighting Requirements

Information note 1:

Information note 2:

Information note 3:

Information note 4:

2.2 Shielding

• (1) The principle of shielding is applied in a way that a dominant permanent building, structure or object which is marked or lighted, or both, obviates the need for marking or lighting other buildings, structures or objects in the immediate surrounding area, which might otherwise be treated as individual obstructions.
• (2) More specifically, the principle of shielding is applied if the marking or lighting, or both, of a dominant permanent building, structure or object is assessed by the Transport Canada regional office as providing sufficient warning to aircraft that, in avoiding the dominant obstruction, they will also avoid the unmarked or unlighted obstructions in the immediate surrounding area without risk of collision.
• (3) Where two similar objects of equal height are situated adjacent to each other, as shown in Figure 2-1, one of the two objects may be considered as shielded, provided the separations listed in Table 2-1 are not exceeded.
  (effective 2016/03/01)

  Table 2-1: Separation between Shielded Objects
  (effective 2016/03/01)

  Height of Objects AGL (metres)	Maximum Separation (metres)
  30 < x ≤ 75	15
  75 < x ≤ 120	23
  120 < x ≤ 200	30
  200 < x ≤ 290	45
  290 < x	60

• (4) A narrow obstruction may be considered as shielded when it is situated with respect to a large obstruction so that an aircraft, whose flight path would avoid the large obstruction would, as a result, also avoid the narrow one.

  

  Text version – Figure 2-1: Adjacent Structures

  Figure 2-1 has two schematics illustrating how an unmarked object can be shielded by an adjacent marked object.

  The first schematic, on the left side, shows dis-similar objects of is a chimney next to a water tower. The second schematic, on the right side, shows similar objects of a chimney next to another chimney.

  In each schematic, the objects are essentially of the same height and one of the objects is marked and this shields the adjacent object which does not thereby need marking.

  The application of shielding is shown as limited to a maximum distance as given in Table 2-2. If the objects are separated by more than this distance, shielding is not possible and both objects would need to be marked.

• (5) Adjacent Catenaries
  • (a) A catenary across a recognized VFR route does not require marking or lighting where it is shielded by a higher catenary.
    (effective 2016/03/01)
  • (b) A catenary segment may be considered as shielded when it is situated within 300 m of the marked catenary of the dominant obstruction so that it remains below a sloping down surface at a gradient of 5% projected from the marked catenary as shown in Figure 2-2.
    (effective 2016/03/01)
  • (c) If the second catenary is above the gradient, this span may not be considered as shielded and is marked or lighted, or both, in accordance with this Standard.

    

    Text version – Figure 2-2: Shielding of Cable Spans

    The Figure 2-2 has two schematics illustrating how shielding can be applied to cable spans, as for example, adjacent spans which cross a river.

    The top schematic shows a three dimensional view of two spans crossing a river, one of which has marker balls on the counterpoise wires. The shielded span does not have marker balls, because it is shielded by the marked span.

    The bottom schematic has dimensions and shows an end view of the transmission line support towers and indicates that shielding is possible when the unmarked span is within a horizontal distance of 300 m from the nearest counterpoise of the marked span and of a height less than an inclined surface of 5 percent which originates from the height of the nearest counterpoise wire of the marked span [the marked span is shown with two counterpoise wires].

    The bottom schematic also shows a third span, as a transmission tower in light grey, which may be located between the marked span and the shielded span. As long as this third span is within the 300 m distance and below the 5 percent incline, it also is shielded and does not need marking.

• (6) Complex Objects
  • (a) Where it is not possible to apply a uniform standard to a cluster of objects such as industrial plants, oil refineries, thermal generating stations, and similar structures, they shall be assessed by the Transport Canada regional office on an individual basis to determine whether or not to treat them as hazards to aviation safety or as an extended obstruction, taking into account the objects' location and height.
  • (b) When treated as an extended obstruction, sufficient marking or lighting, or both, are provided to ensure that the extent of the cluster is defined and visual warning is provided from any angle of aircraft approach.

2.3 Lighting Equipment

• (1) Conformance

  Information note:

  As a basis of ensuring procurement of equipment meets the requirements of this Standard, the person having responsibility or control over the obstruction should obtain an attestation of conformance through an established 3rd Party testing laboratory meeting ISO/ IEC Guide 17025, "General Requirements for the Competence of Testing and Testing Laboratories."
  (effective 2016/03/01).

• (2) Combined Light Units

  Information note:

  The requirements specified in this Standard are written with respect to the performance of obstruction lighting, without consideration of how they are actually designed. Manufacturers may supply light sources contained within a single fitting. For example, a combined CL-864 red flashing beacon with a CL-865 white flashing light, as may be used for a dual medium intensity, configuration "E" installation.

2.4 Environmental Evaluation

Information note:

2.5 Notification Responsibilities
(effective 2016/03/01)

• (1) A person planning to erect or modify an obstruction, namely a building, structure or object, including a moored balloon or kite, either permanently or temporarily, contacts the appropriate regional Transport Canada Civil Aviation office, as specified in Appendix A , at least 90 days prior to erection and provide the information on the planned obstruction, using the Aeronautical assessment form for obstruction marking and lighting as shown in Appendix C.
• (2) If it appears that planned construction might create an obstruction to air navigation in the vicinity of a Department of National Defence (DND) aerodrome, the person having responsibility or control over the construction advises the appropriate DND authorities.

  Information note:

  Aerial cables over navigable waters: Persons planning to construct and/or place a work, including an aerial cable and any structures supporting the cable, should consider the requirements under the Navigation Protection Act (NPA). Under the NPA, all proposed works (including aerial cables) in, on, over, through, across, or under navigable waters listed in the NPA Schedule, may be subject to review and authorization by Transport Canada (TC) Navigation Protection Program (NPP) officials. Therefore, proponents of proposed works over scheduled waters need to contact their local TC NPP office for more information on the process for the review and authorization. It should be noted that the NPA also includes a Minor Works Order. Should the proposed work in a scheduled waterway meet the criteria listed in the Order, the work may proceed without authorization under the Act.

• (3) Any person planning to erect an object also provides information to NAVCANADA, using the "Land Use Proposal Submission Form" (« Projet d'utilisation particulière d'un terrain ») which is available from the appropriate Transport Canada regional office. (See Appendix A)

  Information note:

  Where possible, for objects such as broadcast antennae and wind farms, a sign identifying the owner of the object and providing contact information should be installed at the entrance gate or any other place as appropriate.

2.6 Correction of Lighting Failure
(effective 2016/03/01)

Conspicuity of the obstacle is achieved only when all required marking and lighting is working. Partial equipment failures decrease the margin of safety. Any outage is corrected as soon as possible. Failure of a steady burning side or intermediate light is corrected as soon as possible, but notification is not required.

2.7 Light Failure Notification
(effective 2016/03/01)

Failure or malfunction of lighting is reported immediately to the appropriate Flight Information Centre (FIC) so that a NOTAM can be issued. Failure of a steady burning CL-810 light is corrected as soon as possible, but notification is not required. Toll-free numbers for FICs are listed in Appendix A. The report should contain the following information:

• (a) name of persons or organizations reporting the light failure including any title, address, and telephone number;
• (b) the type of structure;
• (c) location of structure (including latitude and longitude, if known, prominent structures, landmarks, etc.);
• (d) height of structure above ground level (AGL)/above mean sea level (AMSL), if known;
• (e) an estimated return to service date.

Information note 1:

Information note 2:

2.8 Object Height Tolerance
(effective 2016/03/01)

Object height values contained in this Standard have a tolerance of [0, + 2%].

Information note:

Chapter 3 Marking and Markers, General
(effective 2016/03/01)

3.1 Scope

Chapter 3 governs marking requirements for obstructions to air navigation in order to make them conspicuous to pilots during daylight.

3.2 Paint Standards

Where alternate sections of aviation orange and white, referred herein as "orange" and "white" paint markings, are required under this Standard to be displayed on a building, structure or object, the colours of paint markings shall be in accordance with United States Federal Standard FED- STD-595B, for colours identified as:

• (a) orange, 12197; and
• (b) white, 17875.

3.3 Surfaces Not Requiring Paint

• (1) Except as otherwise provided for in Chapter 3, ladders, decks, and walkways of steel towers and similar structures are not to be painted, if a painted surface presents a potential hazard to maintenance personnel.
• (2) Subject to subsection (3), paint may be omitted from precision or critical surfaces, if it would have an adverse effect on the transmission or radiation characteristics of a signal.
• (3) Where markings are omitted under subsection (1) or (2), the overall marking effect of the structure shall not be reduced to the point of compromising the visibility criteria of section 2.1.

3.4 Use of Plastic Wrapping

In the case of poles, where the use of paint is impractical, a wrapping of plastic or other weather resistant material, in the required colours and dimensions, may be applied instead of painting provided that the colour of the wrapping corresponds as close as possible to that required for a painted marking.

3.5 Paint Patterns

Information note:

• (1) Solid Pattern

  A structure is coloured solid orange, if the structure has both horizontal and vertical dimensions not exceeding 3.2 m.

• (2) Checkerboard Pattern
  • (a) Subject to paragraph (c), alternating rectangles of aviation orange and white are displayed on the following types of structure
    • (i) storage tanks for water, gas, grain, and similar tanks,
    • (ii) buildings,
    • (iii) structures that both:
      • (A) appear broad from a side view, that are 3.2 m or more across horizontally, and
      • (B) have a horizontal dimension that is equal to or greater than the vertical dimension.
  • (b) Checkerboard patterns have the following characteristics [refer to Figure 3-1]:
    • (i) for structures having horizontal and vertical dimensions, both greater than 3.2 m, the sides of the checkerboard pattern measure not less than 1.5 m nor more than 6 m,
    • (ii) for structures having horizontal or vertical dimensions, both less than 4.5 m, the sides of the checkerboard pattern may be less than 1.5 m, but not less than 1 m,
    • (iii) the rectangles of the pattern are as nearly square as possible, and
    • (iv) corners are coloured orange.
  • (c) The following exceptions apply to the marking requirements set out in this subsection:
    • (i) storage tanks not suitable for a checkerboard pattern are coloured with alternating bands of aviation orange and white or a limited checkerboard pattern applied to the upper one-third of the structure, and
    • (ii) the skeletal framework of certain water, gas, and grain storage tanks may be excluded, as a result of a risk evaluation, from the checkerboard pattern, where the main structure of the storage tank is large enough that its checkerboard pattern adequately suits the purpose of day marking.

      

      Text version – Figure 3-1: Day Marking - Checkerboard Pattern

      Figure 3-1 shows a page which is a lined grid whose elements [squares] having a page dimension of one quarter inch representing a world distance of 1 m by 1 m. On this grid is drawn a main sequence of checkerboard paint patterns along the diagonal and which increase in size from a solid pattern to patterns of orange and white squares, in two sets of 3 by 3 and three sets of 5 by 5 for a total of 6 patterns. The normal minimum size of the squares is 1.5 m such that a 3 by 3 pattern would cover 4.5 grid elements on each side. A pattern of 5 by 5 with 1.5 m squares would cover 7.5 m on a side.

      The purpose of Figure 3-1 is to illustrate how the number of pattern squares would change with increase of horizontal and vertical dimension. The patterns along the diagonal are symmetrical for horizontal and vertical dimensions. Additional patterns are shown to the left and right of the diagonal to show the effect of changing the horizontal dimension. As one moves away from the diagonal the horizontal dimension is increased for movement to the right or decreased for movement to the left. Movement up the diagonal is for increase in vertical dimension.

      A series of six patterns are arranged on the diagonal and increase in size from ...

      • (1) less than 3.2 m,
      • (2) equal to or greater than 3.2 m,
      • (3) less than 4.5 m,
      • (4) equal to or greater than 4.5 m,
      • (5) less than 7.5 m, and
      • (6) equal to 7.5 m.

      The figure does not show patterns of more than 7.5 m, because (1) there isn't enough space, and (2) the dimensioning becomes obvious from the treatment of lesser size patterns. A note is made that patterns of more than 7.5 m would can have colour square sizes from 1.5 m to 6 m.

      The colour squares of each pattern should not be less than 1.5 m, but where this is not practical because of size of the object itself, the squares are not less than 1 m.

      Note that for Figure 3-1, the case of equal to or greater than 4.5 m is actually shown as 5.0 m such that there are 5 colour squares for this dimension and each colour square is the minimum of 1 m on a side. Thus covering 5 grid elements. If the dimension were between 4.5 m and 5.0 m there would be only a pattern of 3 by 3 squares. The figure was done in this fashion to save space but it is also a weakness and should be corrected in future revision.

      The first pattern on the diagonal, at the lower left of the grid, is an object which is less than 3.2 m on each side. The minimum number of orange and white squares on a side is three, with orange at the corners. The squares of a pattern provided for this size of object would be marginally 1 m and, therefore, it is painted a solid orange rather than a checkerboard. This is also related to the criteria of banding for which objects of less than 3.2 m height are painted a solid orange. Refer Figure 3-2. The first "pattern" is, therefore, not actually a pattern as it is an object painted a solid orange and provided in the figure for purpose of completeness.

      The second pattern on the diagonal is a 3 by 3 pattern which is equal to or greater than 3.2 m on each side. This pattern is shown as covering 4.5 grid elements, with each colour square being 1.5 m on a side.

      The third pattern on the diagonal is again a 3 by 3 pattern which is less than 4.5 m on each side. This pattern is shown as covering 4 grid elements such that the colour squares are 1.33 m. The third pattern is replicated 3 times horizontally to the right to show the effect of increasing the horizontal dimension for (1) equal to or greater than 4.5 m, (2) less than 7.5 m, and (3) equal to 7.5 m. The additional patterns have 3 squares vertically and 5 squares horizontally.

      The fourth pattern on the diagonal is a 5 by 5 pattern. The horizontal and vertical dimensions are increased such that each square can now be at least 1.0 m. Again, the figure takes the "equal to or greater than 4.5 m" as being 5.0 m. The pattern is shown as covering 5 grid elements on each side. The fourth pattern is replicated, twice horizontally to the right to show the effect of increasing the horizontal dimension to (1) less than 7.5 m, and (2) equal to 7.5 m. These additional patterns to the right continue to have 5 colour squares horizontally and 5 colour squares vertically. A further replication is shown to the left of the diagonal, but in this case the horizontal dimension is now less than 4.5 m and the pattern is shown as having 3 squares horizontally and 5 squares vertically.

      The fifth pattern on the diagonal is again a 5 by 5 pattern. The size of the orange and white squares is such that the pattern covers 7 grid elements on a side. Each colour square is 1.4 m. As in the case of the fourth pattern, this pattern is replicated once horizontally to the right for a horizontal dimension of equal to 7.5 m. The pattern is also replicated once horizontally to the left for a horizontal dimension of equal to or greater than 4.5 m. In this case, the horizontal dimension is taken as greater than 5.0 m and the pattern remains as 5 by 5 with colour squares measuring 1.0 m.

      The sixth pattern on the diagonal is also a 5 by 5 pattern. The horizontal and vertical dimensions are 7.5 m such that it is shown as covering 7.5 grid elements with squares measuring 1.5 m. This sixth pattern is replicated twice horizontally to the left for (1) less than 7.5 m and (2) equal to or greater than 4.5 m. In each case, the 5 by 5 format is retained. Again, the dimension of equal to or greater than 4.5 m is taken as 5.0 m.

• (3) Colour Bands
  • (a) Subject to subsection (4), alternate bands of orange and white are displayed on the following types of structure:
    • (i) communications towers and supporting structures of overhead transmission lines,
    • (ii) poles,
    • (iii) chimneys,
    • (iv) skeletal framework of storage tanks and similar structures,
    • (v) wind turbine towers and rotor blades, including the nacelle or generator housing,
    • (vi) cables, conduits, and materials attached to the face of a tower, whether at time of construction or when later added to the structure, and
    • (vii) structures that appear narrow from a side view, that are 3.2 m or more across horizontally, and the horizontal dimension is less than the vertical dimension.
  • (b) Bands applied to structures of any height in excess of 3.2 m [Refer to Figure 3-2]:
    (effective 2016/03/01)
    • (i) are approximately equal in width and to a tolerance of ± 10 percent,
    • (ii) are not more than 30 m wide,
    • (iii) are coloured orange for the top and bottom bands,
    • (iv) have an odd number of bands on the structure, and
    • (v) are in accordance with Table 3-1, except that for each additional 60 m or fraction thereof, one (1) additional orange and one (1) additional white band are added.

    Table 3-1: Structure Height to Number of Bands Requirement

    Structure height (AGL)		blank space
    Greater than (metres)	Not exceeding (metres)	Number of Bands
    0	3.2	solid
    3.2	210	7
    210	270	9
    270	330	11
    330	390	13
    390	450	15
    450	510	17
    510	570	19
    570	630	21

    

    Text version – Figure 3-2: Day Marking - Banded Pattern

    Figure 3-2 is an orthogonal chart showing how the width of the paint bands changes with the height of the structure. The x coordinate is the height of the structure. The y-coordinate is the height of the paint band. The diagonal is x y = 0. The diagonal is the top of the structure including any appurtenance.

    The number of bands changes according to height ranges as indicated in Table 3-1. The number of bands are 7, 9, 11, 13, 15, 17, 19 and 21. The numbers are odd valued because the banding is to start and end in an orange colour.

    The presentation is fan shaped with orange and white bands displayed with increasing width for increased height. From 3.2 m to 210 m there are 7 bands. From 570 m to 630 m there are 21 bands. For the range of 3.2 m to 210 m the maximum width of the band is at the highest height of 210 m and is found from dividing the height by 7 with a result of 30 m. The 30 m maximum occurs for all the ranges. For example, for the range 570 m to 630 m there are 21 bands and the maximum band width is 630 m divided by 21 or 30 m.

    From 0 m to 3.2 m there is no banding and object is painted a solid orange.

• (4) Structures With a Cover or Roof

  If a structure referred to in subsection (3) has a cover or roof whose profile in the line of sight of approaching aircraft is less than 1.5 m, the highest orange band is continued to cover the entire top of the structure. It is acceptable to have the roof made of a solid orange provided that the structure below has a checkerboard pattern.

• (5) Skeletal Structures Atop Buildings

  Where a flagpole, skeletal structure, or similar object is erected on top of a building:

  • (a) the combined height of the object and the building determines whether marking is required; however, only the height of the object determines the width of the colour bands; and
  • (b) if the building is required to have a checkerboard pattern of marking, the object and its height are considered separately for banding determination.
• (6) Appurtenances

  If a tower or similar skeletal structure is required to have banded marking and it also has an appurtenance of more than 12 m, then the combined height of the appurtenance plus that of the main structure determine the width of the banding.

• (7) Partial Marking

  If marking is required for only a portion of a structure because of shielding by other objects or terrain:

  • (a) the width of the bands is determined by the overall height of the structure;
  • (b) a minimum of three bands are displayed on the upper portion of the structure; and
  • (c) in the case of cylindrical storage tanks as shown in Figure 3-3, the checkerboard marking may be applied to the top ½ to 2/3 of the tank.
• (8) Teardrop Pattern

  Spherical water storage tanks with a single circular standpipe support may be marked in a teardrop-striped pattern having the following characteristics:

  • (a) alternate stripes of aviation orange and white are displayed on the tank, as shown in Figure 3-3;
    (effective 2016/03/01)
  • (b) the stripes extend from the top centre of the tank to its supporting standpipe; and
  • (c) the width of the stripes is nearly as equal as possible and the width at the greatest girth of the tank is not to be less than 1.5 m nor more than 6 m.
    (effective 2016/03/01)

    

    Text version – Figure 3-3: Storage Tank Marking

    Figure 3-3 illustrates the marking of storage tanks such as water towers. The tanks may be marked with a checkerboard pattern or with tear-drop shapes for spherical tanks on a stem-like support structure. Room is left in the marking to enable placement of the town name.

    What is important in Figure 3-3 is that it shows that the legs or support structures beneath the tank do not need marking since the marked tank itself is more than sufficient for aircraft daytime warning. In the case of cylindrical water tank without legs, the top 1/2 to 2/3rds of the tank height is painted, leaving the lower portion unpainted.

• (9) Community Names

  If it is desirable to paint the name of the community on the side of a tank, the marking pattern may be broken for a height of not more than 1.0 m to serve this purpose.

3.6 Flag Markers

• (1) Application

  One or several flags may be used as markers instead of paint to indicate the presence of certain structures or objects when it is technically impractical to use spherical markers or painting.

  Information note:

  Some examples of structures or objects where flags may be used are temporary construction equipment, cranes, derricks, oil and other drilling rigs.

• (2) Characteristics

  Flags used as markers under subsection (1) have the following characteristics:

  • (a) Minimum Size - each side of a flag is at least 0.6 m in length;
  • (b) Colour Patterns - they are coloured as follows:
    • (i) if solid, the colour is orange,
    • (ii) if orange and white colours are used, two triangular sections, one aviation orange and the other white, are arranged to form a rectangle, or
    • (iii) a checkerboard pattern of aviation orange and white squares of 0.3 m to a side, is used if the flags are 0.9 m or larger;
  • (c) Shape - they are rectangular in shape and have stiffeners to keep it from drooping in calm wind; and
  • (d) Manner of Display - they are displayed as follows:
    • (i) around, on top, or along the highest edge of the obstruction,
    • (ii) when used to mark extensive or closely grouped obstructions, the flags are displayed approximately 15 m apart, and
    • (iii) the flag stakes are to be of such strength and height that they are able to support the flags above all surrounding ground, structures, or objects of natural growth, as the case may be.

3.7 Omission of Marking with Use of Lighting

A high or medium intensity white flashing lighting system may be used in place of marking if the following conditions are met:

• (a) the lighting system is operated 24 hours a day; and
• (b) in the case of a medium intensity lighting system, the system:
  • (i) is operated 24 hours per day, and
  • (ii) the structure on which it is used is 150 m AGL or less.

Chapter 4 Lighting, General

4.1 Scope

Chapter 4 governs lighting requirements for obstructions to air navigation in order to make them conspicuous to pilots during night time, except as otherwise provided for in this Standard.
(effective 2016/03/01)

Information note:

4.2 Lighting Systems

• (1) Configurations

  Obstruction lighting is displayed on a building, structure or object in one of six configurations, as shown in Figure 4-1 and listed in Table 4-2.

  Information note:

  The following is a listing of light units required under this Standard. Chapter 13 provides detailed characteristics of these light units. Appendix B contains the governing electrotechnical requirements and quality assurance testing.

  Table 4-1: Light Units

  Type	Intensity	Colour	Signal	Flash Rate (fpm)
  CL-810	Low	red	fixed	n/a
  CL-810F	Low	red	flashing	20-40
  CL-864	Medium	red	flashing	20-40
  CL-865	Medium	white	flashing	40
  CL-866, Catenary	Medium	white	flashing	60
  CL-885, Catenary	Medium	red	flashing	60
  CL-856	High	white	flashing	40
  CL-857, Catenary	High	white	flashing	60

  Note 1: In certain cases, some of these lights are supplied as a combined unit (e.g. CL-864/CL-865)

  Note 2: fpm = flashes per minute

  Information note:

  The listing above for "catenary" applies to lighting of the support structures. Catenary wire lights meet the photometric requirements for CL-810.
  (effective 2016/03/01)

  Table 4-2: Lighting Configurations
  (effective 2016/03/01)

  Configuration	Lighting
  A	CL-810 low and CL-864 medium intensity red lighting system
  A'	Alternative red, light reduction to reduce bird fatalities
  B	CL-856 white high intensity (without appurtenance lighting)
  C	CL-856 white high intensity (with CL-865 appurtenance lighting)
  D	CL-865 white medium intensity
  E	Dual CL-810/CL-864 red with CL-865 white medium intensity lighting
  F	Dual CL-810/CL-864 red with CL-856 white high intensity lighting

  

  Text version – Figure 4-1: Configurations of Lighting on Skeletal Structures

  Figure 4-1 illustrates a series of 8 towers for the various configurations of lighting as listed in Table 4-2. The configurations are A to F, illustrated as towers from left to right. The configuration A' is included to show the alternate to configuration A that is used for reducing bird fatalities.

  Towers 1 to 3 are for configurations A and A' which are red lighting systems. Two versions of A' are shown; one with and a second without appurtenance.

  Tower 4 is for configuration B which is high intensity lighting.

  Tower 5 is for configuration C which is high intensity lighting with a single medium intensity light for an appurtenance of more than 12 m height.

  Tower 6 is for configuration D which is medium intensity lighting.

  Towers 7 and 8 are for configurations E and F are dual lighting systems. Configuration E is for medium intensity white lighting combined with a red lighting system. Configuration F is for high intensity white lighting combined with a red lighting system. The white systems are operated during twilight and day and the red system is operated during the night. Where medium intensity is installed on a tower of less than 150 m in height and operated during the daytime, painting can be omitted.

  For configurations A, A', C, D, E and F [excluding configuration B] a medium intensity light is provided for appurtenances of more than 12 m is shown. Note that if the appurtenance is less than 12 m, such light would not be provided.

  For configurations A, A' and D, the height of the light for the appurtenance determines the overall height of the lighting and subsequently the location of the intermediate levels of lighting. For configuration C, the top medium intensity light is an addition and the intermediate levels of high intensity lighting is base on the height of the main structure without appurtenance.

• (2) Red Lighting Systems

  A red obstruction lighting system consists of CL-810 low intensity steady burning aviation red lights and CL-864 medium intensity red flashing aviation beacons.

• (3) CL-865 Medium Intensity White Flashing Lighting Systems

  • (a) A medium intensity white flashing lighting system consists of CL-865 medium intensity flashing white lights used during day/twilight with automatically selected reduced intensity for night time operation.
  • (b) When the system is used on a building, structure or object 150 m AGL or less in height, the marking requirements may be omitted.

    Information note 1:

    No exemption applies from the requirement to display markings on a building, structure or object exceeding 150 m AGL that has a CL-865 medium intensity white flashing lighting system.

    Information note 2:

    This lighting system, except for the rotating type CL-865, is not normally recommended on buildings, structures or objects 60 m AGL or less.
    (effective 2016/03/01)

• (4) High Intensity White Flashing Lighting Systems
  • (a) A high intensity white flashing lighting system consists of CL-856 and CL-857 high intensity flashing white lights used during daytime with automatically selected reduced intensities for twilight and night time operations.
  • (b) When the system is in use, the markings and the other lights required to be displayed on the building, structure or object may be omitted.

    Information note:

    This lighting system should not be used on buildings, structures or objects 150 m AGL or less, unless a risk evaluation shows otherwise.

• (5) Dual Lighting Installation

  • (a) A dual lighting system consists of red lights for night time use and high or medium intensity flashing white lights for daytime and twilight use.
  • (b) When a dual lighting system incorporates medium flashing intensity lights on a building, structure or object 150 m or less in height, or high intensity flashing white lights on a building, structure or object of any height, the marking and the other lighting requirements may be omitted.

4.3 Obstruction Lights During Construction

• (1) As the height of a building, structure or object under construction progressively exceeds each level at which permanent obstruction lights would be required, two or more temporary medium intensity white flashing lights are installed at that level.
• (2) Temporary lighting required under subsection (1) is operated 24 hours a day until all permanent lights required under this Standard are in operation.
• (3) If practical, permanent obstruction lighting required under this Standard shall be installed and operated at each level as construction progresses.
• (4) The lights shall be positioned to ensure that a pilot has an unobstructed view from any angle of approach of at least one light at each level.

4.4 Temporary Construction Equipment Lighting

Information note:

4.5 Groups of Obstructions

• (1) When individual buildings, structures or objects within a group of obstructions are not the same height and are spaced more than 45 m apart, the prominent building, structure or object within the group is lighted in accordance with the standards for individual obstructions of a corresponding height.
• (2) If an outer building or structure is shorter than the prominent one, it is lighted in accordance with the requirements for individual obstructions of a corresponding height.
• (3) Light units required under this section are placed to ensure that the light is visible to a pilot approaching from any direction.
• (4) In addition to the requirement set out in subsection (3), at least one flashing beacon is installed at the top of a prominent centre obstruction or on a special tower located near the centre of the group.
• (5) If there is no prominent centre obstruction, a risk evaluation shall be performed to assess the location of the applicable beacons.

4.6 Glare from Flashing Obstruction Lights

• (1) Where obstruction lighting is likely to distract operators of aircraft, railway trains, surface vessels, and other vehicles, or if the lighting is in a congested residential area, a suitable shield is installed on the appropriate lights to minimize the glare effects of the light.
• (2) The application of such shielding shall not diminish the required performance of the light as specified in Chapter 13 of this Standard for obstruction identification to pilots.
• (3) Shielding applied to the exterior of the light unit is suitable for environmental conditions such as snow, ice and frost cover, so that the light output is not degraded from that required by this Standard.
• (4) In the proximity of navigable waterways or along coastal regions, the installation of an obstruction lighting system is coordinated with marine authorities by the owner or operator of the obstruction in order to avoid interference with marine navigation.

4.7 Monitoring of Obstruction Lights

The objective of monitoring is to enable the owner to maintain the lighting system in operation without failure. The occurrence of light failure is detected so that a NOTAM can be issued and repair action undertaken in a timely fashion.
(effective 2016/03/01)

• (1) The owner of a structure with a flashing obstruction light system is responsible:
  (effective 2016/03/01)
  • (a) to know there is occurrence of any failure, by observation once every 24 hours, either visually or through observation of a remote indicator designed to show failure of such lighting regardless of position or colour. For medium and high intensity lighting and dual lighting systems, observation is made for at least the day and night modes of operation; and
  • (b) to have a documented program of at least annual inspection of all automatic or mechanical control devices, indicators, and alarm systems associated with the structure lighting to ensure that the such apparatus is functioning properly.
• (2) The owner is exempt from paragraph 4.7(1)(b) where the alarm system has self-diagnostic features to confirm the communication link and operational status of the monitoring system itself at least once every 24 hours.
  (effective 2016/03/01)
• (3) Where it is not possible to observe either visually or through means of a remote indicator, the objective of monitoring is accomplished through provision of lamps having a rated life of more than one year of operation and establishment of a documented program of at least annual inspection.
  (effective 2016/03/01)
• (4) For each structure, a log is maintained showing the history of observations, inspections, failures, repairs, and relamping, as applicable for the method of monitoring used.
  (effective 2016/03/01)
• (5) The owner of the structure advises NAV CANADA, as soon as possible, of any obstruction light failure so that a NOTAM can be initiated in accordance with paragraph 2.7(1).
  (effective 2016/03/01)

  Information note:

  Each flashing light system, in accordance with Appendix B, is to have a controller which gives indication of the status of both the flashing lights and any associated steady burning lights. The controller has provision to permit connection to a remote alarm indicator (supplied by others or as an option)
  (effective 2016/03/01)

  Figure 4-2 illustrates a variety of methods for monitoring. Method (a) is the use of an alarm system for failure indication only. Method (b) determines the status of all the lights in a 24 hour period, which may be considered as a form of self-diagnosis.

  Since it is the responsibility of the owner to know of a failure, Method (b) may be chosen over Method (a) in consideration of reliability. If the failure alarm is given only at the time of occurrence, will the communication link and overall monitoring system be functioning properly to transmit the alarm to the owner?

  Method (c) is an instance for which it is not possible to provide a communications link. For this method the objective of monitoring is accomplished through the use of lamps having a rated life of more than one year of operation combined with at least annual inspection and relamping. In the case of LED sources the owner may choose to not re-lamp based on experience; annual inspection, however, should still take place.

  In the case of Method (d), monitoring would not normally be required as it is not a flashing light system. However, inspection and relamping should be undertaken as in Method (c).

  

  Text version – Figure 4-2: Methods of Monitoring

  Figure 4-2 illustrates four methods of monitoring obstacle lights, shown left to right. The variation is with respect to the means of communication to a remote indicator which is shown in the bottom left of the figure. It is of importance to note that the primary consideration of variation is for communication and not for the controller. Provision of a controller at the tower location is a requirement for all flashing systems in accordance with Appendix B of Standard 621.

  Method (a) is where there is communication from the controller for only a failure alarm. That is, the alarm is provided only when failure occurs. Use of long life lamps having an operational life of more than a year and annual inspection are required as mitigation.

  Method (b) is where there is capability for 24 hour status indication. This enables not only a knowledge of a failure, but also to know whether the communication means is functioning properly. As mentioned in the Standard 621 text, where this method is used, the provision of long life lamps and annual inspection can be omitted.

  Method (c) is where provision of a communication link is not possible. The Standard 621 text states mitigation is through use of long life lamps having an operational life of more than a year and annual inspection.

  Method (d) is included for completeness and is for where a controller is not provided at the tower. This is typically where the lights are only the steady burning CL-810. This method, however, is similarly mitigated through use of long life lamps and annual inspection.

4.8 Placement Factors

• (1) The height of a building, structure or object above ground (AGL) is used to determine the number of light levels required to be installed as part of a lighting system.
• (2) The height of light levels required to be installed may be adjusted slightly, but not to exceed 3 m, when necessary to accommodate guy wires and personnel who replace or repair light fixtures.
• (3) Except for catenary support structures, the following factors are considered when determining the placement of obstruction lights on a building, structure or object:
  • (a) for a red obstruction lighting system or a medium intensity white flashing lighting system, the overall height of the structure including all appurtenances such as rods, antennae, obstruction lights and similar objects, determine the number of light levels;
  • (b) for a high intensity white flashing lighting system,
    • (i) the overall height of the main structure excluding all appurtenances is used to determine the number of light levels, and
    • (ii) if required, a CL-865 medium intensity flashing light is displayed on the highest portion of any antenna or other appurtenance supported by the main structure; and
  • (c) for a dual obstruction lighting system, the determination of the number of light levels is in conformity with the pertinent requirements for white and red lighting systems.
• (4) The elevation of the tops of adjacent buildings or structures in congested areas is used as the equivalent of ground level to determine the proper number of light levels required.
• (5) If an adjacent building, structure or object shields any light, horizontal placement of the lights is adjusted or additional lights are mounted on that object to retain or contribute to the definition of the obstruction.

4.9 Ice Protectors

• (1) Where icing is likely to occur, metal grates or similar protective means are installed directly over each light unit required under this Standard to be installed on a building structure or object to prevent falling ice or accumulations from damaging the light units.
• (2) The protective means are of a design and manner of placement such that the required photometric output of the fixtures is not affected.

Chapter 5 Red Obstruction Lighting System, Configuration "A"

5.1 Scope

Chapter 5 governs obstruction lighting that uses a configuration "A" lighting system.

Information note:

5.2 System Requirements

• (1) General
  • (a) A configuration "A" red obstruction lighting system, as shown in Figure 5-1, consists of one or several CL-864 red flashing beacons or CL-810 steady burning red lights, or a combination thereof.
    (effective 2016/03/01)
  • (b) When red lighting alone is used for night protection, no exemption to markings for day protection required under this Standard is allowed.
    (effective 2016/03/01)
  • (c) Refer to Chapter 13 for control of red lighting systems.
    (effective 2016/03/01)

    Information note:

    The CL-810 comes in two forms; a single unit [one lamp and one globe] and a double unit [two lamps and two globes].

• (2) Single CL-810 Obstruction Light Units

  Where more than one obstruction light is required either vertically or horizontally, or where maintenance can be accomplished within a reasonable period of time, single unit CL-810 lights may be used as follows:

  • (a) Top Level atop structures such as airport ILS buildings and long horizontal structures such as perimeter fences and building roof outlines; or
  • (b) Intermediate Level at intermediate levels on skeletal or solid structures when more than one level of lights is required to be installed and there are two or more single units per level.
• (3) Double Obstruction Light Units

  Subject to subsection (2), when used as a top light or in areas or locations where the failure of a single unit could cause an obstruction to be totally unlighted, double unit CL-810 lights are installed at each end of a row of single unit obstruction lights, and more specifically as follows:
  (effective 2016/03/01)

  • (a) Top Level on a structure, building or object 45 m AGL or less, one or more double unit lights operating simultaneously are installed at the highest point;
  • (b) Intermediate levels,
    • (i) double unit lights are installed when a malfunction of a single unit light could create an unsafe condition and in remote areas where maintenance cannot be performed within a reasonable time, and
    • (ii) both lamps of the double unit operate simultaneously or a transfer relay is used to switch to the inactive lamp should the active lamp fail; and
  • (c) Lowest Level at the lowest level of a building, structure or object,
    • (i) light units may be installed at a higher elevation than standard if the surrounding terrain, trees or any adjacent buildings would obscure the lights, or
    • (ii) in certain exceptional instances, as determined by a risk evaluation, the lighting otherwise required for the lowest level may be omitted.
• (4) Flashing Display

  When one or more levels of lights are comprised of CL-864 flashing beacons, the lights flash simultaneously.
  (effective 2016/03/01)

• (5) Equivalent Method of Displaying Obstruction Lights

  Provided that approval is obtained following the result of a risk evaluation, lights may be placed on poles equal to the height of the building, structure or object required to be lighted, and may be installed on or adjacent to such building, structure or object.

5.3 Poles, Radio and Television Towers and Similar Skeletal Structures
(effective 2016/03/01)

The following requirements apply to radio and television towers, supporting structures for overhead transmission lines, and similar structures. Refer to Figures 5-1 and 5-2.

• (1) On the topmost part of a structure:
  • (a) 45 m AGL or less, two or more CL-810 steady burning lights are installed in a manner to ensure an unobstructed view of one or more lights by a pilot; or
    (effective 2016/03/01)
  • (b) exceeding 45 m AGL, at least one CL-864 red flashing beacon is installed in a manner to ensure an unobstructed view of one or more lights by a pilot.
    (effective 2016/03/01)
• (2) On the intermediate levels of a structure:
  • (a) the number of levels of lights is in accordance with Figure 5-1;
  • (b) the number of lights at each level is determined by the shape and height of the structure;
  • (c) the lights are installed so as to provide an unobstructed view of at least one light by a pilot from any angle of approach;
  • (d) where CL-810 steady burning red lights are installed on:
    • (i) a structure 105 m AGL or less, two or more steady burning red lights are installed on diagonally or diametrically opposite positions, and
    • (ii) a triangular shaped structure 105 m AGL or less:
      • (A) two red light units, single or double, are installed, provided that at least one can be viewed unobstructed by a pilot from any angle of approach, or
      • (B) where the requirement specified in clause (A) is impractical, three red light units are installed, one on each apex of the triangular cross-section, or
    • (iii) a structure exceeding 105 m AGL, a CL-810 steady burning red light is installed on each outside corner at each level; and
      (effective 2016/03/01)

  • (e) where CL-864 flashing red beacons are used on a structure exceeding 105 m AGL, the CL-864 lights at intermediate levels are installed on the outside of the tower structure on diagonally or diametrically opposite positions at each level.
    (effective 2016/03/01)

    

    Text version – Figure 5-1: Configuration A: Red Lighting Installation

    Figure 5-1 is an orthogonal chart for location of red lights on a tower. The x-coordinate is the height of the tower and the y-coordinate is the height of the lights. The location of the top light is on the diagonal ... x - y = 0. The chart has inclined lines representing the location of the lights. The number of levels and type of light whether CL-810 or CL-864 are indicated by dashed lines and solid heavy lines respectively.

    The number of levels of lighting changes according to seven height ranges and these are titled using the FAA designations of A0, A1, A2 to A6. The number of levels is double the designation number, except for A0. For example, in the case of the height range A2 from 105 m to 210 m, there are four levels of lighting and the type of lighting alternates so that there is a top CL-864, then downwards after an interval a set of CL-810 lights, then a mid level of a set of CL 864 lights, followed by a the lower level of a set of CL-810 lights. For other height ranges the same principle of alternation CL-864 and CL-810 lights is followed. The top light is always a flashing CL-864 for ranges A1 to A6.

    In the case of the A0 range from 0 m to 45 m there is only one level and this is normally a dual CL-810 top light.

    Within the A2 range there are four levels of lighting including the top light. The inclined lines on the chart represent level heights of 1/4, 1/2, 3/4 and 1. For say an overall height of 150 m, this represents 37.5 m, 75 m, 112.5 m and the top light at 150 m. The chart is only for illustration and does not have sufficient resolution to permit reading precise values from the chart itself. Instead the designer obtains the values mathematically. Where there are 4 levels and the overall vertical height is say 150 m, this is divided by 4 to give a 37.5 m interval or spacing. A3 has six levels and the interval is found by dividing the overall height by 6. The A4 height is divided by 8, and so forth.

    

    Text version – Figure 5-2: CL-810 and CL-864 Lights on Towers

    Figure 5-2 shows the manner of installation for lighting as applied to a tower. The Figure 5-1 addressed the vertical spacing of the lights. Figure 5-2 addresses the number and placement of lights for particular levels. For lattice-work towers, the lights are installed external to the structure, since, if installed inside the structure, the light emission would be blocked by structural members.

    The top light is normally a single CL-864 medium intensity light. Except that for towers less than 45 m, in which case the top light is a dual unit CL-810 for purpose of redundancy.

    For intermediate levels the light units are installed at the ends of the diagonals so as to be viewable from 360 degrees. This includes lower levels of CL-864 lights. In the case of an intermediate level of CL-810 lights, single units are normally used but dual units may be used to facilitate planned repair action.

• (3) Appurtenances

  Where a building, structure or object required to be lighted includes an appurtenance such as a rod, antenna, or similar extension, a topmost light is installed above the main part of the building, structure or object in accordance with the provisions of this subsection.

  • (a) Where the appurtenance is 12 m or less in height and:
    • (i) is incapable of supporting a red flashing beacon, the beacon may be placed at the base of the appurtenance, or
    • (ii) if the mounting location does not allow unobstructed viewing of the beacon by a pilot from any angle of approach, additional beacons are added.
  • (b) Where the appurtenance exceeds 12 m in height and:
    • (i) is incapable of supporting a red flashing beacon, a supporting mast with one or more beacons is installed adjacent to the appurtenance, and
    • (ii) the adjacent installation of (i) does not exceed the height of the appurtenance and is within 12 m of the tip of the appurtenance to allow the pilot an unobstructed view of at least one beacon, from any angle of approach.

    Information note:

    The primary focus of "appurtenance" is to enable installation of a short rod, antenna or similar extension of less than 12 m in height without lighting. It is not intended that the feature of "appurtenance" would involve extensions that are significantly in excess of 12 m. In such an instance, the extension is to be considered as adding to the height of the main object.
    (effective 2016/03/01)

5.4 Alternative Configuration A' to Reduce Bird Fatalities
(effective 2016/03/01)

• (1) An alternative Configuration A' is applied for the purpose of reducing bird fatalities and consists of only CL-864 lights, as shown in Figure 5-3, for object heights of more than 105 m.
  (effective 2016/03/01)
• (2) For A1 heights of more than 45 m to 105 m, the CL-810 lights are made to flash at the same rate as the top mounted CL-864 light.
  (effective 2016/03/01)

  Information note:

  The alternate Configuration A' is only applicable to towers and similar skeletal structures.
  (effective 2016/03/01)

  

  Text version – Figure 5-3: Alternative Configuration A' - Lighting Reduction to Reduce Bird Fatalities

  Figure 5-3 is an orthogonal chart for the alternative Configuration A' to reduce bird fatalities. The chart is the same as that of Figure 5-1 for configuration A, with omission of steady burning CL-810 lights, except for height ranges A0 [0 m to 45 m] and A1 [45 m to 105 m]. The steady burning CL-810 lights are considered to be attractive to birds which subsequently fly around the tower and are killed by collision with the guy wires. Thus the alternative for omission of CL-810 steady burning lights.

  For the range A1, from 45 m to 105 m, there is the one CL 864 top light and one intermediate level of CL-810 lights. Since there is only the one CL-864 top light, it is desirable to retain the lower CL-810 lights in case of failure of the top light. Otherwise, with failure, the total length of the tower would be left unlighted. The CL-810 lights, however, are made to flash at the same rate as the CL-864 top light.

  For the A0 range the single top light of steady burning CL-810 is retained because towers of this height are typically without guy wires.

5.5 Chimneys, Flare Stacks and Similar Solid Structures

• (1) Number of Light Units per Level

  Subject to subsection (3), the number of lights to be installed at the top and at each level of a chimney, flare stack or similar solid structure depends on the diameter of the structure and is in accordance with Table 5-1.

  Table 5-1: Number of lights
  (effective 2016/03/01)

  Diameter	Minimum Number of Lights at top and per level
  ≤ 6 m	3
  6 m < x ≤ 30 m	4
  30 m < x ≤ 60 m	6
  x > 60 m	8

• (2) Top Mounted Obstruction Lights
  (effective 2016/03/01)
  • (a) For structures 45 m AGL or less, CL-810 lights are installed horizontally at regular intervals at or near the top.
  • (b) For Structures Exceeding 45 m AGL, at least three CL-864 beacons are installed.
  • (c) For chimneys, cooling towers, and flare stacks, lights may be displayed as low as 6 m below the top to avoid the obscuring effect of deposits and heat generally emitted by this type of structure.
  • (d) For flare stacks, as well as other structures associated with the petrol-chemical industry, depending upon assessment, normal lighting requirements may not be necessary. This could be due to the location of the flare stack/structure within a large well-lighted petrol-chemical plant or the fact that the flare, or working lights surrounding the flare stack/structure, is as conspicuous as obstruction lights.

    Information note:

    It is important that the lights be readily accessible for cleaning and lamp replacement.
    (effective 2016/03/01)

• (3) Mounting Intermediate Levels
  (effective 2016/03/01)
  • (a) Steady Burning (CL-810) Lights. The number of light levels is obtained from Figure 5-1. At least three lights are installed on each level.
  • (b) Flashing (CL-864) Beacons. The number of beacon levels may be obtained from Figure 5-1. At least three lights are installed on each level, and
    • (i) for structures 105 m AGL or less, intermediate levels of flashing lights are not required, and
    • (ii) for structures exceeding 350 feet (107 m) AGL at least three flashing (CL-864) beacons should be installed on each level in a manner to allow an unobstructed view of at least one beacon.
• (4) Hyperbolic Cooling Towers

  Where any cooling tower:
  (effective 2016/03/01)

  • (a) is 180 m in height or less AGL, intermediate light levels may be omitted; or
  • (b) exceeds 180 m AGL in height, a second level of light units is installed approximately at the midpoint of the structure and in a vertical line with the top level of lights.

5.6 Prominent Buildings and Similar Extensive Obstructions

• (1) Subject to subsection (4), individual obstructions having a similar height above ground and located not more than 45 m apart within a group of obstructions may be considered as an extensive obstruction for lighting purposes, in which case the group displays steady burning red lights to indicate the extent of the obstruction as specified in this section.
• (2) On a structure 45 m or less in both horizontal dimensions:
  (effective 2016/03/01)
  • (a) a CL-810 light is displayed on the highest point at each end of the major axis of the obstruction; or
    (effective 2016/03/01)
  • (b) a dual CL-810 light is displayed in the centre of the highest point.
    (effective 2016/03/01)
• (3) On a structure exceeding 45 m in at least one horizontal dimension:
  (effective 2016/03/01)
  • (a) CL-810 lights are displayed on:
    (effective 2016/03/01)
    • (i) the highest point at each end of the obstruction, and
    • (ii) the highest points for each 45 m, or fraction thereof, for the overall length of the major axis.
  • (b) If the minor axis of a structure exceeding 45 m in one of its horizontal dimensions is 45 m or less in length, the lights referred to in paragraph (a) may be installed as a row along the middle or along either side, as shown in Figure 5-4.
    (effective 2016/03/01)
  • (c) If a structure exceeding 45 m in any horizontal dimension is located near a landing area and two or more edges of the structure are of the same height, the edge nearest the landing area is lighted with CL-810 lights.
• (4) Structures Exceeding 45 m AGL
  • (a) Top Lights - CL-810 steady burning red lights are installed on the highest point at each end.
    (effective 2016/03/01)
  • (b) At intermediate levels of the structure,
    • (i) CL-810 steady burning red lights are displayed for each 45 m or fraction thereof,
      (effective 2016/03/01)
    • (ii) the vertical position of the intermediate lights is equidistant between the top lights and the ground level as the shape and type of obstruction will permit, and
    • (iii) one CL-810 steady burning red light is displayed at each outside corner on each level with the remaining lights evenly spaced between the corner lights.
• (5) Exceptions

  Flashing red CL-864 beacons may be used instead of CL-810 steady burning lights if early or special warning to pilots is necessary, provided that, in the case of an extensive obstruction:
  (effective 2016/03/01)

  • (a) they are displayed on the highest points of the obstruction, at intervals not exceeding 900 m; and
  • (b) at least three beacons are displayed on one side of the obstruction to indicate a line of lights.

    

    Text version – Figure 5-4: Prominent Buildings Lighting

    Figure 5-4 has a number of schematics illustrating the location and spacing of CL-810 lights on prominent buildings.

    The spacing on the top of the building and vertically along the sides is in increments of 45 m or less depending on the horizontal, depth or vertical dimensions of the building.

    Horizontal is across the page. Vertical is up the page. Depth is into the page.

    If both the horizontal and depth dimensions [a roof top] are less than 45 m, two CL-810 lights are placed at the ends of the major axis or a dual light is installed at the centre.

    In the case of a building having a depth of less than 45 m and a horizontal dimension of more than 45 m, the lights can be installed along a major horizontal axis at the top or on one side of the top closest to the aerodrome [referred to as the "landing area side"].

5.7 Bridges

• (1) A bridge assessed through a risk evaluation as a likely hazard to aviation safety has CL-864 red flashing lighting, as shown in Figure 5-5.
  (effective 2016/03/01)
• (2) If the bridge referred to in subsection (1) is over navigable water, the obstruction lighting installer consults with the Coast Guard to avoid interference with signals to marine navigation.

  

  Text version – Figure 5-5: Bridge Lighting

  Figure 5-5 illustrates the installation of obstacle lighting on a bridge. The bridge as shown in Figure 5-5 is a cantilever bridge with two sets of uprights, one set near each end. Red flashing CL-864 lights are installed on the top of the uprights.

  Note is made in the figure that it is illustrative of a typical application. An actual bridge may need additional lighting.

5.8 Groups of Objects

• (1) When objects within a group of obstructions are approximately the same overall height AGL and are located not more than 45 m apart, the group of obstructions may be considered an extensive obstruction and lighted in accordance with section 5.6.
  (effective 2016/03/01)

  Information note:

  Where the objects are not more than 45 m apart, the grouping effectively simulates a building for the pilot as shown in Figure 5-6. The lights are installed as shown in Figure 5-3 and some of the objects may be unlighted.
  (effective 2016/03/01)

• (2) Where individual objects, except wind turbines, within a group of closely spaced obstructions may or may not be of the same height and the spacing between individual structures is not in all cases equal to or less than 45 m apart:
  (effective 2016/03/01)
  • (a) the prominent objects within the group are lighted in accordance with the standards for individual obstructions of a corresponding height;
  • (b) if the outer structure is shorter than the prominent, the outer structure is lighted in accordance with the standards for individual obstructions of a corresponding height; and
  • (c) at least one flashing beacon is installed at the top of a prominent centre obstruction or on a special tower located near the centre of the group.

    Information note:

    The emphasis is on "closely spaced" and for which the central beacon can serve for protection of the overall group. Because of the variation, the installation should be subject to assessment by Transport Canada Civil Aviation.
    (effective 2016/03/01)

    

    Text version – Figure 5-6: Groups of Objects

    Figure 5-6 has two schematics illustrating the installation of red lighting for groups of objects.

    For the top schematic, the objects are of the same height and resulting spacing of individual CL-810 lights installed on individual objects would not be more than 45 m.

    The objects in the top schematic are shown in front of a light grey rectangle. The intent is to imply that although the lights are on separate objects, the effect at night would that of an extensive object and not of a series of objects which individually would not be seen by the pilot.

    For the bottom schematic, the objects are not of the same height and the spacing of resulting light application is less than 45 m. A prominent structure at the centre of the group is provided with a CL-864 light. Or a special tower or pole provided for this purpose.

5.9 Characteristics of Lights

Lighting displayed on a bridge has the light characteristics specified in Chapter 13.

5.10 Ice Shields
(effective 2016/03/01)

Where icing is likely to occur and metal grates or similar protective ice shields are installed directly over each light unit to prevent falling ice or accumulations from damaging the light units, the lights are mounted in a manner to ensure an unobstructed view of at least one light by a pilot approaching from any direction.

Chapter 6 Medium Intensity White System, Configuration "D"
(effective 2016/03/01)

6.1 Scope

Chapter 6 governs obstruction lighting that uses a configuration "D" lighting system.

Information note:

6.2 Application

Use of CL-865 medium intensity white flashing light units:
(effective 2016/03/01)

• (a) during daytime and twilight with automatically selected reduced intensity for night time operation;
  (effective 2016/03/01)
• (b) where used on a building, structure or object 150 m AGL or less in height, day marking [painting] otherwise required under Chapter 3 can be omitted; and
  (effective 2016/03/01)
• (c) are designed so that all lights on the tower flash synchronously.
  (effective 2016/03/01)

Information note:

6.3 Characteristics

• (1) Photometrics

  The photometric output of a configuration "D" lighting system is in accordance with Table 13–2.

• (2) Control

  The lighting system is in accordance with Table 13-1 for day, twilight and night modes of operation.

6.4 Radio and Television Tower and Similar Skeletal Structures

• (1) Subject to subsection (4), on a radio or television tower, or similar skeletal structure, the number of light levels to be installed depends on the height of the structure, including antennae and similar appurtenances, and is determined in accordance with Figure 6-1.

  Information note:

  The location of the topmost light [as may be installed for an appurtenance] determines the overall height of the structure and thus the intermediate levels. If lighting is installed on a tower and an appurtenance is later installed, additional lighting may be applied to address the appurtenance without changing the location of lighting originally installed on the tower. The additional lighting, however, is designed to flash synchronously with the original lighting. This is intended for appurtenances not significantly more than 12 m. The lighting should be modified if the addition to the object is significantly more than 12 m in height.
  (effective 2016/03/01)

• (2) Top Level

  One or more light units are installed at the highest point of a skeletal structure to provide 360-degree coverage ensuring an unobstructed view.

• (3) Intermediate Levels

  At an intermediate level of a skeletal structure, two CL-865 beacons are mounted outside, at diagonally or diametrically opposite positions of the intermediate level.

• (4) Lowest Level

  At the lowest level of light units of a skeletal structure:

  • (a) the light units may be installed at a higher elevation than that required under this section for the structure, if the surrounding terrain, trees, or any adjacent building would obscure the light units; and
    (effective 2016/03/01)
  • (b) in circumstances determined by a risk evaluation, the light units may be omitted.

    

    Text version – Figure 6-1: Medium Intensity White Flashing Lighting System; Configuration D

    Figure 6-1 is an orthogonal chart for Configuration D lighting and similar to Figure 5-1, except in this case the lighting is that of medium intensity white flashing CL-865 lights. This is a white flashing system and there are no CL-810 red steady burning lights. At night the light intensity is reduced to 2000  cd, but continues to be white in colour.

    The CL-865 lights are at the same level and location as the CL-864 in Figure 5-1. Since there are no CL-810 lights, the number of the range is the number of levels. For example D2 has 2 levels of lighting. D3 has 3 levels of lighting. And so forth.

    The height ranges are titled by the designations of D1, D2, D3 ... to D6. There is no D0 range as installation of strobe type CL-865 lights below 60m is not recommended. When this lighting is installed for towers 150 m or less in height, and operated 24 hours [that is, including daytime], painting can be omitted. The use of medium intensity lighting is allowed above 150 m, but painting is required.

• (5) Structures 150 m AGL or Less
  (effective 2016/03/01)

  When white lights are used during nighttime and twilight only, marking is required for daytime. When operated 24 hours a day, other methods of marking and lighting are not required.

• (6) Structures Exceeding 150 m AGL
  (effective 2016/03/01)

  The lights should be used during nighttime and twilight and may be used 24 hours a day. Marking is always required for daytime.

• (7) Appurtenances

  An appurtenance is lighted in accordance with the requirements specified in subsection 5.3(3), except as far as the use of the CL-865 light in place of CL-864 light is concerned.

6.5 Chimneys, Flare Stacks, and Similar Solid
Structures

• (1) Lighting Levels and Location

  The number of levels of light units required to be installed on a chimney, a flare stack or similar solid structure is determined in accordance with Figure 6-1.

• (2) Number of Light Units per Level

  The number of light units required to be installed on each level of a solid structure referred to in subsection (1), is determined in accordance with Table 5-1.

6.6 Hyperbolic Cooling Towers

A hyperbolic cooling tower is lighted in accordance with the requirements specified in section 5.4.

6.7 Prominent Buildings and Similar Extensive Obstructions

When objects within a group of obstructions are approximately the same overall height above the surface and are located a maximum of 45 m apart, the group of obstructions may be considered an extensive obstruction. Install light units on the same horizontal plane at the highest portion or edge of prominent obstructions. Light units are placed to ensure that the light is visible to a pilot approaching from any direction. Lights are displayed to indicate the extent of the obstruction as follows:
(effective 2016/03/01)

• (1) Structures 45 m or Less in All Horizontal Directions
  (effective 2016/03/01)
  • (a) Display at least one light on the highest point at each end of the axis of the obstruction.
  • (b) If (a) above is impractical because of the overall shape, a double obstruction light is displayed in the centre of the highest point.
• (2) Structures Exceeding 45 m in at Least One Horizontal Direction
  (effective 2016/03/01)
  • (a) Display at least one light for each 45 m or fraction thereof, of the overall length of the major axis.
  • (b) At least one of these lights required in (a) is displayed on the highest point at each end of the obstruction.
  • (c) Additional lights are displayed at approximately equal intervals not to exceed 45 m on the highest points along the edge between the end lights.
  • (d) If an obstruction is located near a landing area and two or more edges are the same height, the edge nearest the landing area is lighted.
• (3) Structures Exceeding 45 m AGL
  (effective 2016/03/01)
  • (a) Lights are installed on the highest point at each end.
  • (b) At intermediate levels, lights are displayed for each 45 m, or fraction thereof.
  • (c) The vertical position of these lights is equidistant between the top lights and the ground level as the shape and type of obstruction will permit.
  • (d) One light of (c) is displayed at each outside corner on each level with the remaining lights evenly spaced between the corner lights.

    Information note:

    Due to the glare factor, caution should be used in the application of strobe-type medium intensity white flashing lights.
    (effective 2016/03/01)

6.8 Bridges

A bridge is lighted in accordance with the requirements specified in section 5.6.

Chapter 7 High Intensity White System, Configuration "B" and "C"
(effective 2016/03/01)

7.1 Scope

Chapter 7 governs obstruction lighting that uses a configuration "B" and "C" lighting system.

7.2 Application

When a high intensity white flashing lighting system is operated 24 hours a day, the marking requirements and the other applicable lighting requirements for an obstruction may be omitted.

Information note:

7.3 Characteristics

• (1) Photometrics

  The photometric output of a high intensity white flashing lighting system is in accordance with Table 13-2.

• (2) Control

  The lighting system is controlled in accordance with Table 13-1 for day, twilight and night modes of operation.

7.4 Installation

• (1) Vertical Aiming

  In order to avoid potential glare problems, the vertical aiming angle of a CL-856 light unit used in a high intensity white flashing system is as follows:

  • Location

    (a) the unit is adjusted to compensate for its height above ground, in accordance with Table 7-1; and

    Table 7-1: Vertical Aiming of HI Light Units
    (effective 2016/03/01)

    Location of light unit AGL (metres)	Beam angle adjustment (degrees)
    x ≥ 150 m	0
    122 ≥ x > 150 m	1
    92 ≥ x > 122 m	2
    92 m > x	3

  • Terrain

    (b)

    • (i) where terrain, nearby residential areas, or other situations dictate, the light beam of a light unit may be further elevated above the horizontal,
    • (ii) the main beam of light unit located at the lowest level of a building, structure or object shall not strike the ground closer than 5 km from the building, structure or object,
    • (iii) if additional adjustments are necessary, light units may be individually adjusted upward, in 1 degree increments, starting at the bottom of the building structure or object,
    • (iv) excessive elevation, however, may reduce conspicuousness by raising the beam above a collision course flight path,
    • (v) where the lighting system is installed on a building, structure or object located near a highway, waterway, or airport approach area, shielding or vertical or horizontal aiming adjustments, or both, shall be made as necessary to avoid causing glare, and
    • (vi) adjustment of light units shall not derogate from the conspicuousness requirement set out in section 2.1 of this Standard.
• (2) Relocation or Omission of Light Units

  Where any light units are obstructed from view by a building, structure or object, including surrounding terrain and trees, the following actions may be taken:

  • Lowest Level

    (a) In the case of the lowest level of lights:

    • (i) as shown in Figure 7-1, the light units may be installed at a higher elevation than that required under Chapter 7, and
      (effective 2016/03/01)
    • (ii) in circumstances determined by a risk evaluation, the light units may be omitted.
      (effective 2016/03/01)
  • Two Adjacent Structures

    (b) As shown in Figure 7-2 and Figure 7-3, in the case of adjacent buildings or structures:
    (effective 2016/03/01)

    • (i) if two buildings or structures are situated within 150 m of each other and their respective light units are installed at similar levels, the light units on the sides of the buildings or structures facing each other may be omitted provided that all lights on both structures flash simultaneously, except for adjacent catenary support structures,
    • (ii) vertical placement of the lights to either or both structures' intermediate levels is adjusted to place the lights on the same horizontal plane,
    • (iii) where one building or structure is higher than the other, one or more complete levels of light units, as the case may be, is installed on that part of the higher building or structure that extends above the top of the lower structure, and
    • (iv) if the structures are of such heights that their respective levels of lights cannot be placed in identical horizontal planes, the levels of light units are placed such that the centre of the horizontal beam patterns does not face toward the adjacent building or structure.
      (effective 2016/03/01)

      Information note:

      For example, based on subparagraph (iv) above, structures situated north and south of each other will have the light units on both structures installed on a northwest/southeast and northeast/southwest orientation.

  • Three or More Adjacent Structures

    (c) the treatment of a cluster of structures as an individual or a complex of structures is determined by way of a risk evaluation, taking into consideration the location, heights, and spacing with other structures.

    

    Text version – Figure 7-1: Adjacent Building

    Figure 7-1 is the first of a group of figures that includes Figures 7-2 and 7-3, illustrating the repositioning of lighting levels or omission of lights on chimneys when there is an adjacent building or chimney. Figure 7-1 shows an upward movement by 10 m to 90 m for the lowest level of lighting [of 3 levels] which was originally at 80 m, because this level would otherwise be at the same height as the adjacent 80 m building and the light emission may be blocked by appurtenances on the top of the building for directions of aircraft approach.

    

    Text version – Figure 7-2: Lighting Adjacent Structures

    Figure 7-2 is the second of the group of figures showing omission of lights on a chimney where there is an adjacent chimney. This figure has 2 schematics.

    The left-hand schematic shows omission of inner lights where the spacing of the chimneys is less than 150m and both chimneys are of the same height at a representative 180 m. The outside lights of each tower provide the necessary warning and the inner lights which would not be easily seen by the pilot can be omitted.

    The right-hand schematic shows a case for which one of the chimneys is 240 m in height and the adjacent smaller chimney is 180 m in height. The inner lights of the lower levels can be omitted but all the top lights of the 240 m chimney are retained because they are not shielded by the adjacent 180 m tower.

    All the lights on both chimneys flash in synchronism.

    

    Text version – Figure 7-3: Lighting Adjacent Structures

    Figure 7-3 has two schematics and is the third and last of the series of figures illustrating repositioning of light levels of adjacent chimneys. The chimneys are separated by not more than 150 m.

    The left-hand schematic shows a 230 m chimney adjacent to a smaller 120 m chimney. The inner lights can be omitted, but the difference in height of the levels of the two chimneys is too great such that repositioning to place the levels in the same horizontal plan is not possible.

    The right-hand schematic shows a 240 m chimney adjacent to a smaller 180 m chimney and for which the levels can be repositioned since the amount of movement is not excessive. For the 240 m chimney, having 3 levels, the lower level at 80 m is moved upwards by 5 m. The mid level of the 180 m chimney originally at 90 m is moved downwards by 5 m. This places the lower levels of each chimney in the same horizontal plane at 85 m.

    In the right-hand schematic the 2nd level of lights on the 240 m chimney at 160 m are moved upwards by 20 m. This movement is large but is the only solution, since the top level of lights of the adjacent 180 m chimney cannot be moved downwards so as to place these lights in the same horizontal plane as the moved 2nd level of lighting on the 240 m chimney. The top lights on the 180 m chimney are likely already moved downwards by 6 m to avoid contamination from the exhaust.

    All lights on both chimneys flash in synchronism.

7.5 Radio and TV Towers and Similar Skeletal Structures

• (1) Top Level
• On a radio, TV tower or similar skeletal structure, one level of light units is installed within 3 m of the highest point of the main structure.

  (2) Intermediate Levels

  On a skeletal structure referred to in subsection (1):

  • (a) the number of levels of light units to be installed depends on the height of the structure, excluding any appurtenances, and is determined in accordance with Figure 7-4; and
    (effective 2016/03/01)

    Information note 1:

    The number of levels for the high intensity lights of Configuration B is determined from the height of the main structure excluding any appurtenance. Where the appurtenance exceeds 12 m, a medium intensity light is installed on the top of the appurtenance or within 12 m of the top of the appurtenance and the combination of lighting is Configuration C.
    (effective 2016/03/01)

    Information note 2:

    It is intended that Configuration C is to address appurtenances that are not significantly in excess of 12 m. Where the appurtenance is significantly in excess of 12 m the Minister may deem a portion of such appurtenance to be considered a part of the main structure and lighting to be provided accordingly.
    (effective 2016/03/01)

  • (b) at least three lights are installed on each intermediate level and mounted to ensure that the effective intensity of the full horizontal beam coverage is not impaired by the structural members.
• (3) Appurtenances

  Where a skeletal structure has an appurtenance in excess of 12 m in height above it:

  • (a) a medium intensity white flashing light is installed in accordance with subsection 6.4(5); and
  • (b) the light referred to in paragraph (a) operates 24 hours a day and flashes simultaneously with the rest of the lighting system installed on the structure.

    

    Text version – Figure 7-4: High Intensity White Flashing System - Configuration B and C

    Figure 7-4 shows an orthogonal chart for high intensity CL-856 and CL-865 white lighting on a tower. The x coordinate is the height of the tower and the y-coordinate is the height of the lights. The chart has inclined lines representing the location of the lights.

    The number of levels of lighting changes according to five height ranges which are designated as B2, B3, B4 ... to B6. The ranges start at B2 which is 150 m to 210 m. The number of levels of lighting is the same as the number used in the range designation. For example, the B2 range has 2 levels of high intensity lighting. There is no B0 or B1 range for reason that high intensity lighting is not recommended below 150 m.

    The chart shows a heavy line for the top of the main structure and then a higher heavy dashed line to represent an appurtenance of more than 12 m which requires installation of a CL-865 light above the top high intensity light. Where there is no CL 865 light [that is, an appurtenance of less than 12 m], the configuration itself would be designated as Configuration B. When there is a CL-865 light with high intensity lighting on the main structure, the configuration is designated as Configuration C.

    The height of the high intensity lights for both Configuration B and Configuration C is determined from the overall height of the main structure which does not include the height of the appurtenance.

7.6 Chimneys, Flare Stacks and Similar Solid Structures

• (1) Lighting Levels and Location

  Subject to subsection (3), the number of levels of light units required to be installed on a chimney, flare stack or similar solid structure is determined in accordance with Figure 7-4.
  (effective 2016/03/01)

• (2) Number of Light Units per Level

  The number of light units required to be installed on each level of the high intensity white flashing lighting system of a structure referred to in subsection (1), is determined in accordance with Table 5-1.
  (effective 2016/03/01)

• (3) Hyperbolic Cooling Towers

  Where any cooling tower of a nuclear generating station:

  • (a) is 180 m in height or less AGL, intermediate light levels may be omitted; or
  • (b) exceeds 180 m AGL in height, a second level of light units is installed approximately at the midpoint of the structure and in a vertical line with the top level of lights.

    

    Text version – Figure 7-5: Hyperbolic Cooling Tower

    Figure 7-5 illustrates the placement of lights on the top circumference of a hyperbolic cooling tower.

    The number of lights is related to the diameter of the tower at the location of installation. Three lights for a diameter less than 6 m. Four lights for a diameter of 6 m to 30 m. Six lights for a diameter of 30 m to 60 m. Eight lights for diameters of more than 60 m. The quantity of lights per diameter is also obtained from Table 5-1.

7.7 Prominent Buildings, Structures and Similar Extensive Objects

• (1) Individual buildings, structures or objects having a similar height above ground and located not more than 60 m apart within a group of obstructions may be considered as an extensive obstruction for lighting purposes, in which case the group displays CL-856 white flashing light units to indicate the extent of the obstruction as specified in this section.

  Information note:

  Owing to the glare factor, caution shall be used in the application of high intensity white flashing lights.

• (2) On a structure 60 m or less in both horizontal dimensions, a CL-856 light is displayed in the centre of the highest point.
  (effective 2016/03/01)
• (3) Structures Exceeding 60 m in any Horizontal Dimension
  • (a) On a structure exceeding 60 m in any horizontal dimension, CL-856 light units are displayed on:
    • (i) the highest point at each end of the obstruction, and
    • (ii) the highest points for each 60 m, or fraction thereof, for the overall length of the major axis.
  • (b) If the minor axis of a structure exceeding 60 m in one of its horizontal dimensions is 60 m or less in length, the lights referred to in paragraph (a) may be installed as a row along the middle or along either side, as shown in Figure 5-3.

• (4) If the obstruction exceeds 60 m in both horizontal dimensions, light units should be equally spaced along the overall perimeter of the obstruction at intervals of 60 m or fraction thereof.
  (effective 2016/03/01)

• (5) Structures Exceeding 150 m AGL
  • (a) Top Lights - A CL-856 white flashing light unit is installed on the highest point at each end of a structure exceeding 150 m AGL in height.
  • (b) At intermediate levels of the structure,
    • (i) a CL-856 white flashing unit is displayed for each 150 m or fraction thereof,
    • (ii) the vertical position of the intermediate lights is equidistant between the top lights and the ground level as the shape and type of obstruction will permit, and
    • (iii) a CL-856 white flashing unit is displayed at each outside corner on each level with the remaining lights evenly spaced between the corner lights.

Chapter 8 Dual Red/White Medium Intensity System, Configuration "E"
(effective 2016/03/01)

8.1 Scope

Chapter 8 governs obstruction lighting that uses a configuration "E" lighting system consisting of CL-­810 steady burning red and CL-864 flashing red obstruction light units for nighttime operation and CL-865 medium intensity white flashing light units for daytime and twilight operation.

Information note:

8.2 Application

• (1) The light units of the system are installed as required by the relevant provisions of:
  • (a) Chapter 4 for lighting in general;
  • (b) Chapter 5 for red lighting; and
  • (c) Chapter 6 for medium intensity lighting.
• (2) The number of light levels needed is obtained from Figures 5-1 and 6-1 for the applicable components of the lighting system.

• (3) Where the lighting is a medium intensity light and is a combined CL-865/CL-864 light unit, and it is intended that the CL-865 not be installed less than 60m height, the CL-864 is at the same location as the CL-865.
  (effective 2016/03/01)

8.3 Operation

The lighting system is operated such that:

• (a) both the red CL-864/CL-810 and white CL-865 systems are not operated at the same time;
  (effective 2016/03/01)
• (b) there is no more than a 2-second delay when changing from one system to the other; and
• (c) outage of one of two lamps in the uppermost CL-864 red flashing beacon or outage of any uppermost red light causes the white CL-865 obstruction lighting system to operate in its specified "night" step intensity.
  (effective 2016/03/01)

Information note:

8.4 Control Device

The lighting system is controlled such that:

• (a) a photocell device causes a change of operation from red to white lighting with an increase and decrease of the ambient light level;
• (b) the system automatically changes from white to red and subsequently from red to white when the northern sky illuminance, as indicated in Table 13-1, goes through the transitions of twilight to night and night to twilight respectively; and
• (c) where a malfunction requires the CL-865 white lighting system to be operated during the night, the device causes operation at the lower intensity level.
  (effective 2016/03/01)

8.5 Antenna or Similar Appurtenance Light

When a structure utilizing this dual lighting system is topped with an antenna or similar appurtenance exceeding 12 m in height above the structure:

• (a) a CL-865 medium intensity white flashing light and a CL-864 red flashing beacon is placed within 12 m from the tip of the appurtenance;
• (b) the CL-865 white light operates during daytime and twilight and the red light during nighttime; and
• (c) the lights required in paragraphs (a) and (b) flash simultaneously with the rest of the lighting system.

8.6 Omission of Marking

When medium intensity white CL-865 lights are operated on a structure 150 m AGL or less during daytime and twilight, the markings required under this Standard may be omitted on the structure.
(effective 2016/03/01)

Chapter 9 Dual Red/White High Intensity System, Configuration "F"
(effective 2016/03/01)

9.1 Scope

Chapter 9 governs obstruction lighting that uses a configuration "F" lighting system referred to in Table 4-2.

Information note:

9.2 Light Units

CL-810 and CL-864 red light units shall be used for night time lighting and CL-856 high intensity white flashing light units shall be used for daytime and twilight lighting.

9.3 Installation

The light units required under section 9.2 are installed in accordance with the relevant provisions of Chapter 4 for lighting in general, of Chapter 5 for red CL-864/CL-810 lighting and Chapter 7 for high intensity white CL-856 flashing lighting.
(effective 2016/03/01)

9.4 Operation

A configuration "F" lighting system:
(effective 2016/03/01)

• (a) is operated in accordance with the requirements of:
  (effective 2016/03/01)
  • (i) Chapter 4 for lighting in general,
  • (ii) Chapter 5 for red lighting, and
  • (iii) Chapter 7 for high intensity white flashing lighting;
• (b) does not have both red and white lighting systems operating at the same time; however, there is no more than a 2-second delay when changing from one colour of lighting system to the other; and
  (effective 2016/03/01)
• (c) where an outage of one of two lamps in the uppermost CL-864 red beacon or an outage of any uppermost red light unit occurs, have the white CL-856 lighting switched on and operating in its specified night mode of intensity.
  (effective 2016/03/01)

9.5 Control Device

The light intensity of a configuration "F" lighting system is controlled by a photocell device set to operate in accordance with Table 13-1 for transition between day, twilight and night.
(effective 2016/03/01)

9.6 Antenna or Similar Appurtenance Light

• (1) Where a configuration "F" lighting system is used on a building, structure or object that is topped with an antenna or similar appurtenance exceeding 12 m in height above it, both a CL-864 medium red flashing and a CL-865 medium intensity white flashing light unit is placed within 12 m from the tip of the appurtenance.
• (2) The white light unit referred to in subsection (1) operates during daytime and twilight, and the red light unit during night time.

9.7 Omission of Marking

When high intensity white flashing light units are operated during daytime and twilight, any day marking otherwise required under Chapter 3 to be displayed on the building, structure or object may be omitted.

Chapter 10 Marking and Lighting of Catenaries

10.1 Scope

Chapter 10 governs obstruction marking and lighting of a catenary wire and a catenary support structure.

Information note:

10.2 Marking of Catenary Support Structures

A support structure of a power line is painted in alternate bands of orange and white in accordance with subsection 3.5(3), and is clear of trees and brush insofar as practicable. [refer to information note in section 2.1.]
(effective 2016/03/01)

10.3 Markers
(effective 2016/03/01)

• (1) Structure Markers
  (effective 2016/03/01)

  Markers are used to highlight support structures when it is impractical to make the structures conspicuous by painting. Markers may also be used in addition to aviation orange and white paint when additional conspicuity is necessary for aviation safety. They should be displayed in conspicuous positions on or adjacent to the structures so as to retain the general definition of the structure. The markers are recognizable in clear air from a distance of at least 1200 m and in all directions from which aircraft are likely to approach. The markers are distinctively shaped, i.e., spherical or cylindrical, so they are not mistaken for items that are used to convey other information. They are replaced when faded or otherwise deteriorated.
  (effective 2016/03/01)

• (2) Shore Markers
  (effective 2016/03/01)

  Where the marking of a support structure would not clearly indicate the presence of a catenary over a waterway, shore markers are displayed as indicated in Figure 10-1, and:
  (effective 2016/03/01)

  • (a) painted aviation orange and white; and
  • (b) are either of:
    (effective 2016/03/01)
    • (i) a panel type, designed as a 6 m square panel with a 5 m diameter aviation orange dot, or
    • (ii) a pole type.

10.4 Catenary Markers

Spherical markers are displayed on a catenary, as indicated in Figure 10-1 and as specified below, unless equivalent markings are approved by the Minister as a result of a risk assessment:

Text version – Figure 10-1: Catenary Markers

Figure 10-1 has two schematics illustrating markers and markings for catenaries such as that of a transmission line catenary over a river.

The top schematic shows a plan view of the catenary. Marker balls are installed on the two counterpoise wires. The balls are alternately orange and white in colour. Since the placement is in an alternate or zig-zag fashion, one catenary has only white balls and the second has only orange balls.

The bottom schematic shows a profile looking upriver. The support structures on each side of the river are with orange and white banding. The catenary itself has ball markers. Since this is a profile from the perspective of the pilot, the two counterpoise wires merge and what is seen in this schematic is only the alternating orange and white ball markers.

The bottom schematic shows 4 types of markers/marking: ball markers on the counterpoise wire; banding of the towers; on the left side of the river, a pole marker having orange and white banding; and, on the right side of the river, a 5 m diameter solid orange circle on a 6 m square white panel. Although not specifically stated in Figure 10-1, which of these markers and marking to be used for a particular site is dependent upon assessment.

• (1) Dimensions and spacing

  Each marker has the following diameters and associated spacings on the catenary:

  • (a) 50  cm diameter and 30 m spacing;
  • (b) 75  cm diameter and not more than 45 m spacing;
    (effective 2016/03/01)
  • (c) 90  cm and not more than 60 m spacing;
    (effective 2016/03/01)
  • (d) 150  cm diameter and 90 to 120 m spacing;

  • (e) other dimensions or shapes are used provided the projected area of such markers is not less than that presented by a spherical marker or can be recognized in clear air from a distance of at least 1000 m; and
    (effective 2016/03/01)

  • (f) 50  cm diameter installed in critical areas near runway ends at a spacing of 10 m to 15 m.
    (effective 2016/03/01)

• (2) Minimum Quantity

  Where the length of the catenary span is less than twice the spacing, depending on the size of marker as that indicated in subsection (1), not less than two markers are used.

• (3) Location

  Markers are displayed:

  • (a) on the highest wire or by other means at the same height; or
  • (b) where there is more than one wire at the highest level, the markers may be installed alternately along each wire, as indicated in Figure 10-1, as long as the apparent distance between adjacent markers as seen by the pilot [horizontally and perpendicular to the wires] meets the spacing standard.
    (effective 2016/03/01)

    Information note:

    This method will allow the weight and wind loading factors to be distributed.

• (4) Colour Pattern

  Markers have the following colour patterns:

  • (a) on overhead wires, they are marked by alternating solid colour spheres of orange and white;
  • (b) an orange marker is placed at each end of the overhead wire and its spacing adjusted to accommodate the rest of the markers; and
  • (c) when less than four markers are needed, they are all orange.

10.5 Omission of Marking

Marking of a catenary wire or a support structure may be omitted, where:

• (a) the height of the support structure is 150 m AGL or less, and CL-866 lights are installed on the support structure and operated 24 hours a day; or
• (b) CL-857 high intensity white flashing light units are installed on the support structure and operated 24 hours a day.

10.6 Lighting of Catenary Wires

• (1) Light units are installed along a catenary wire, either separately or in combination with a day marker, provided that the light units are:
  • (a) used on transmission line catenary near airports, heliports, across rivers, canyons, lakes, and similar geographical features;
  • (b) visible by a pilot from any normal angle of approach;
  • (c) meet the requirements specified for the CL-810 light unit;
  • (d) installed on the highest energized line;
    (effective 2016/03/01)
  • (e) located within 6 m of the day marker if the light unit is separate from the day marker; and
  • (f) spaced at the same interval as that required for the day markers on the same catenary.

• (2) Lighting of catenary wires is not required where lighting in accordance with section 10.7 or 10.8 is installed, unless otherwise determined following a risk assessment.

  Information note:

  Where catenary wire lights and markers cannot be installed on the catenary itself [e.g. a gondola lift], installation may be made on a separate line in a manner that provides an equivalent level of safety.
  (effective 2016/03/01)

  

  Text version – Figure 10-2: Catenary Wire Lights

  Figure 10-2, has 4 schematics, illustrating wire lights [lights installed on the energized lines] for a catenary over a river. The wire lights provide night protection, the marker balls provide day protection.

  The top schematic shows a plan view. The wire lights are alternately installed on the energized lines at the same effective spacing as the marker balls.

  The middle two schematics indicate; (1) the allowed maximum vertical distance of 6 m between the wire lights and marker balls, and (2) a combined marker ball and CL-810 lights. The CL-810 lights are located on the top and bottom of the marker ball.

  The bottom schematic shows a profile view looking upriver for which the pilot would see the marker balls on the upper counterpoise wires and below this the wire lights on the energized lines.

10.7 Lighting of Catenary Support Structures
(effective 2016/03/01)

• (1) Where a support structure or a power line crossing are assessed by the Minister, as a result of an Aeronautical Evaluation, as likely to be inadequately indicated by painting and markers specified in Chapter 10, the support structure is lighted in daytime by medium CL-866 or high intensity CL-857 white flashing light units as follows and as illustrated in Figure 10-3:
  (effective 2016/03/01)
  • (a) The lighting is operated at night at reduced intensity.
    (effective 2016/03/01)
  • (b) Where residential complaint would result from the use of white lighting, a dual system of CL-866/CL-885 or CL-857/CL-885 may be installed.
    (effective 2016/03/01)
  • (c) The lighting systems are identified as Configurations S1, S2, S3, S4 and S5 as listed in Table 13-2 and illustrated in Figure 10-4.
    (effective 2016/03/01)
  • (d) Where a catenary wire crossing requires three or more supporting structures, the inner structures are equipped with enough light units per level to provide a full 360 degree coverage.
    (effective 2016/03/01)
  • (e) High intensity CL-857 or dual high intensity CL-857/CL-885 systems are not recommended on structures 150 m or less in height unless an aeronautical study shows otherwise.
    (effective 2016/03/01)

    

    Text version – Figure 10-3: Catenary Flashing Lights

    Figure 10-3 has two schematics illustrating catenary lights and their special sequence of flashes.

    The top schematic shows a profile view of the catenary looking upriver. The lights are installed on each side of the river on the support structures. Depending upon site characteristics, one or more of the levels of lighting may be installed on terrain below the associated support tower. The bottom and middle lights have 180 degree coverage with beam centre aimed perpendicular to the river. The top light has 360 degree coverage.

    The bottom schematic shows the flash sequence on a linear chart with the x coordinate representing time. The flash sequence of middle-to-top-to-bottom repeats at a rate of once per second. The lighting flash rate is 60 flashes per minute. The increments of the flash sequence are 13ths of a second. The middle light flashes first at zero time. The top light then flashes after 1 increment or at 1/13th of a second. The bottom light then flashes at twice the increment or at 3/13ths of a second. The sequence repeats after completion of 10 times the increment at 3/13ths plus 10/13ths equals 13/13ths or 1 second.

    

    Text version – Figure 10-4: Catenary Configurations

    Figure 10-4 illustrates the 5 configurations of catenary lighting which are referred to as "styles".

    Style 1 is composed of CL-866 medium intensity white flashing lights for day, twilight and night operation.

    Style 2 is a dual system composed of CL-866 medium intensity white flashing lights for day and twilight operation and CL 885 medium intensity red flashing lights for night operation.

    Style 3 is composed of CL-857 high intensity white flashing lights for day, twilight and night operation.

    Style 4 is a dual system composed of CL-857 high intensity white flashing lights for day and twilight operation and CL-885 medium intensity red flashing lights for night operation.

    Style 5 is composed of CL-885 medium intensity red flashing lights.

    For dual systems, lights are installed on top of each other so that there is no blockage of light output in either day or night operation. The CL-857, CL-866 and CL-885 have a flash rate of 60 flashes per minute.

• (2) Support Structures 150 m AGL or less

  • (a) When medium intensity white lights CL-866 are operated 24 hours a day, or when a dual red/medium intensity system CL-866 daytime & twilight/CL-885 nighttime is used, marking is omitted.
    (effective 2016/03/01)
  • (b) When using a medium intensity white light CL-866 or a flashing red light CL-885 during twilight or nighttime only, painting is used for daytime marking.
    (effective 2016/03/01)
• (3) Support Structures exceeding 150 m AGL
  • (a) When high intensity white lights CL-857 are operated 24 hours a day, or when a dual red/high intensity system CL-857 daytime and twilight/CL-885 nighttime is used, marking can be omitted.
    (effective 2016/03/01)
  • (b) When a flashing red obstruction light CL-885, a medium intensity CL-866 flashing white lighting system or a high intensity white lighting system CL-857 is used for nighttime and twilight only, painting is used for daytime marking.
    (effective 2016/03/01)
• (4) Levels of Light Units

  The lighting system includes light levels displayed as follows:

  • (a) a system of three levels of sequentially flashing light units is installed on each supporting structure or adjacent terrain as follows:
    • (i) at the top of the structure,
    • (ii) at the lowest point in the catenary, and
    • (iii) approximately midway between the other two light levels and at least 15 m from the other two levels, except that the middle light level may be deleted when the distance between the top and the bottom light levels is less than 30 m,
  • (b) the maximum vertical spacing tolerance allowed to accommodate structural limitations is 20 percent of the uniform spacing of the bottom and middle light units, and
  • (c) if the base of the supporting structure is higher than the lowest point in the catenary, such as a canyon crossing, the required light units are installed on the adjacent terrain at the level of the lowest point in the catenary.
• (5) Light Coverage

  The photometric coverage requirements for the light units are:

  • (a) in the case of the top level of light units:
    • (i) one or more lights are installed, subject to subparagraph (ii), at the top of the structure to provide 360-degree coverage ensuring an unobstructed view to a pilot from any normal angle of approach,
      (effective 2016/03/01)
    • (ii) if the installation presents a potential danger to maintenance personnel, or when necessary for lightning protection, the top level of light units may be mounted not more than 6 m below the highest point of the structure, provided that due consideration is given to the overall obstacle avoidance distances referred to in section 2.1, and
  • (b) in the case of the middle and bottom levels of light units:
    • (i) the light units at the middle level and bottom level are installed so as to provide a minimum of 180-degree coverage cantered perpendicular to the flyway,
    • (ii) where a catenary crossing is situated near a bend in a river, canyon or similar geographical feature, or where it is not perpendicular to the flyway, the horizontal beam is directed to provide the most effective light coverage to warn pilots approaching the catenary wires from any normal angle of approach, and
    • (iii) where a catenary involves three or more supporting structures, the inner structure or structures are equipped with enough light units per level to provide 360-degree coverage.
• (6) Flash Sequence The lighting system flashes as follows:
  • (a) each light unit has a flash frequency of 60 flashes per minute or 1 second per flash cycle (± 5 percent),
  • (b) the flash sequence of the levels of light units is middle, top, and then bottom,
  • (c) the interval between top and bottom flashes is about twice the interval between middle and top flashes, and
  • (d) the interval between the end of one sequence and the beginning of the next is about 10 times the interval between middle and top flashes.
• (7) Synchronization

  On the lighting system used for associated catenary support structures:

  • (a) the corresponding light levels flash simultaneously, if practicable, and
  • (b) where three or more supporting structures are involved and the inner structure or structures are equipped with enough light units per level to provide 360-degree coverage, the light units for each level flash simultaneously.
• (8) Photocell Control

  Where a medium or high intensity lighting system is used for a catenary crossing, the light intensity of the system is automatically controlled by photocell devices whose day, twilight and night transition settings conform to the specifications set out in Chapter 13.
  (effective 2016/03/01)

• (9) Photometric Characteristics

  The photometric characteristics of the lighting system are in accordance with the requirements set out in Chapter 13.

10.8 Lighting with use of Aircraft Detection System (ADS)
(effective 2016/03/01)

As determined by a risk assessment and approved by the Minister, where an Aircraft Detection System (ADS) is installed as specified in Chapter 15, each support structure may be lighted by one of the following medium intensity lighting systems as illustrated in Figure 10-2b:
(effective 2016/03/01)

• (a) a CL-866 medium intensity white flashing white lighting system, or
• (b) a CL-866/CL-885 dual medium intensity flashing lighting system.

Information note:

Text version – Figure 10-5: Catenary Flashing Lights with ADS

Figure 10-5 illustrates an installation of reduced lighting where an Aircraft Detection System (ADS) is used. In this instance, the support structures have only the one top light which may be a CL-866 medium intensity white flashing light or dual CL-866/CL-885 medium intensity white/red flashing light. The use of this reduced lighting is determined by assessment.

10.9 Site Maintenance / Clearance
(effective 2016/03/01)

The area in the vicinity of the catenary and support structure base should be clear of all items and/or objects of natural growth that could interfere with the line-of-sight between a pilot and the obstacle marking/lighting.

Chapter 11 Marking and Lighting of Tethered Objects
(effective 2016/03/01)

11.1 Scope

• (1) Chapter 11 governs the marking and lighting of tethered objects including moored balloons and kites.
  (effective 2016/03/01)

• (2) This chapter does not address tethered objects intended to be released prior to full extension of the tether, such as glider winching operations for which the ground attached tether is exposed in the air for a short period of time.
  (effective 2016/03/01)

11.2 Tethered Objects Less than 150 m AGL
(effective 2016/03/01)

11.2.1 Application

A balloon that is 1.8 m or more in diameter or exceeds 3 cubic metres of gas capacity, or a kite weighing more than 2.27 kg are marked and lighted in accordance with the requirements specified in Chapter 11.

11.2.2 Markers

Markers are attached, during daytime, to the mooring lines of a balloon or to the tether cable of a kite in accordance with this section.

• (1) Location

  Markers are displayed at not more than 15 m intervals along the mooring lines of the balloon or the tether cable of the kite, beginning at 45 m from the point of attachment on the ground.

• (2) Characteristics

  Markers required under subsection (1) are:

  • (a) rectangular in shape, 0.15 m wide and 3.0 m in length; and
  • (b) of the following colour patterns:
    • (i) solid orange, or
    • (ii) of two triangular sections, one of aviation orange and the other aviation white, combined to form a rectangle.

11.2.3 Lighting

At night, a moored balloon or a kite is equipped with the lighting devices specified in this section.

• (1) Location
  • (a) Lights having the characteristics specified in subsection (2) are located on the top of the object in a fashion as to be viewable from all directions, except that where the dimensions of the object are in excess of 45 m, additional lights of the same type are installed on the top, nose section, tail section, and on the mooring lines or tether cable approximately 5 m below the balloon or kite, so as to define its shape and size; and
  • (b) Additional lights are equally spaced along the mooring line or tether cable for each 107 m, or fraction thereof, commencing at 90 m AGL.
• (2) Characteristics

  For operations from 90 m AGL to 150 m AGL, red flashing or white flashing lights of 32.5 effective candelas are installed on the moored balloon and on its mooring lines, or on the tether cable of the kite.
  (effective 2016/03/01)

• (3) Control

  Lighting required on a moored balloon or on a kite is provided with a means of control such as, for instance a photocell, for day and night time operation in accordance with Table 13-1.

11.3 Tethered Objects more than 150m AGL
(effective 2016/03/01)

Tethered objects of more than 150m AGL are provided with day and night protection using white high intensity CL-856 lights, or dual white high intensity / red medium intensity CL-856/CL-864 lights located and operated as for skeletal objects as detailed in Chapter 7 and Chapter 9.
(effective 2016/03/01)

Chapter 12 Marking and Lighting of Wind turbines and Wind farms
(effective 2016/03/01)

12.1 Scope

Chapter 12 governs the marking and lighting of wind turbines of a wind farm having overall heights (hub height plus vertical blade height) of up to 315 m, and of meteorological towers.
(effective 2019/12/15)

Information note 1:

Information note 2:

Information note 3:

12.2 Wind turbines of Total Height Equal to or Less than 150 m

• (1) Marking Requirements – Day Protection
  (effective 2016/03/01)

  • (a) For a single wind turbine and wind turbines of a wind farm, having a solid silhouette, the rotor blades, nacelle and upper 2/3 of the supporting mast are painted an aviation white or an off-white colour. White colours have a luminance factor Y of not less than 0.80. Off-white colours have a luminance factor Y of not less than 0.57.
    (effective 2019/12/15)

  • (b) A wind turbine with a lattice-work support mast has the mast painted in bands of orange and white as for skeletal structures (refer Chapter 4).
    (effective 2019/12/15)

    Information note:

    Colours that are acceptable to FED-STD-595 or RAL are set out in the following table:
    (effective 2019/12/15)

    Table 12-1. Wind turbine paint colours
    (effective 2019/12/15)

    FED-STD-595	RAL	x	y	Y
    17875 White Int'l	blank space	0.321	0.343	80.9
    	9002 Grey-White	0.319	0.340	68.8
    	9003 Signal white	0.314	0.332	86.0
    	9010 Pure white	0.320	0.338	87.4
    	9016 Traffic white	0.316	0.334	88.5
    36495 Light gray	blank space	0.311	0.333	57.7
    	7035 Light grey	0.312	0.333	57.8

    RAL - Reichs-Ausschuß für Lieferbedingungen und Gütesicherung

• (2) Lighting Requirements – Twilight and Night Protection
  (effective 2016/03/01)

  For Night Protection, a single wind turbine and wind turbines of a wind farm are lighted as illustrated in Figure 12-1 and as follows:

  • (a) For a single wind turbine:
    • (i) A wind turbine is lighted with use of a CL-864 light unit for twilight and nighttime operation for horizontal turbines or a CL-865 light unit for daytime, twilight and nighttime operation for vertical turbines as shown in Figure 12-1; and
      (effective 2016/03/01)
    • (ii) The lighting fixtures required under subparagraph (i) are mounted to ensure an unobstructed view by a pilot approaching from all angles of aircraft approach.
  • (b) For a wind farm:
    • (i) The group of wind turbines composing a wind farm is indicated to pilots by installation of CL-864 medium intensity red flashing lights on specified wind turbines on the perimeter of the wind farm.
      (effective 2019/12/15)

      Information note:
      (effective 2019/12/15)

      Certain wind farms may extend over a large area and might be considered as consisting of groups of windturbines. In such instance the Minister may require that the "perimeter" is that of individual groups of windturbines in order to maintain a 900 m spacing of the top lights.

    • (ii) The lights of subparagraph (i) are located so as to define the wind farm perimeter and spaced at a distance of approximately 900 m. Wind turbines at corners of the wind farm are lighted.
      (effective 2019/12/15)
    • (iii) In addition to the CL-864 lights of subparagraph (ii) the dominant [highest height above mean sea level (AMSL)] wind turbine within the wind farm is also required to be lighted. This requirement for lighting is dependent upon the degree of dominance deemed to produce a hazard to air navigation. The Minister may require lighting on more than one inner wind turbine, depending upon the dimensions of the wind farm.
      (effective 2019/12/15)
    • (iv) A tower or other structure within the wind farm, which in being lighted provides the same level of safety, may be used for installation of a CL-864 light to provide the 900 m spacing.
      (effective 2019/12/15)
    • (v) Because of the variation in configuration of wind farms, the provision of lighting is also subject to an aeronautical assessment taking into account such factors as the general profile of the group, the location of the wind farm in relation to nearby aerodromes or recognized VFR flight routes, and the anticipated air traffic.
      (effective 2019/12/15)
    • (vi) All CL-864 lighting provided for a wind farm flash simultaneously.
      (effective 2019/12/15)

  

  Text version – Figure 12-1: Lighting Wind turbines; Heights up to 150 m AGL

  Figure 12-1 has two schematics illustrating application of lighting for windturbines of up to 150 m in height. The top schematic shows installation of a single CL-864 light on the nacelle for horizontal windturbines and a CL-865 at the top of the support mast for vertical windturbines. The qualification of horizontal and vertical relates to the shaft that is driven by the rotating blades. In Canada essentially all windturbines are of the horizontal type.

  The bottom schematic shows the application of CL-864 lights on selected windturbines at a spacing of approximately 900 m along the perimeter of the windfarm and a CL-864 light on a dominant windturbine within the windfarm.

12.3 Wind turbines of Total Height Exceeding 150 m

• (1) Marking Requirements - Day Protection
  (effective 2016/03/01)
  Refer to subsection 12.2(1)
  (effective 2019/12/15)
• (2) Lighting Requirements
  (effective 2016/03/01)

  For wind turbines of more than 150 m to 315 m in overall height:
  (effective 2019/12/15)

  • • (a) Two CL-864 lights are installed on the nacelle, as illustrated in Figure 12-2. Only one light operates at a time; the second light serving as backup in case of failure of the operating light. The lights are installed on top of each other so that the output of an operating light is not blocked by the standby light for angles of approach or are installed with a horizontal separation of not less than 1 m.
      (effective 2019/12/15)
    • (b) For a solid support mast, at least three CL-810 lights are installed for an intermediate level at half the nacelle height (± 10 m) and configured to flash at the same rate as the CL-864 light on the nacelle.
      (effective 2019/12/15)
    • (c) The CL-864 lights are installed:
      (effective 2019/12/15)
      • (i) in such a manner as to provide an unobstructed view for aircraft approaching from any direction.

    Information note 1:
    (effective 2019/12/15)

    A stalled blade is not considered a light obstruction feature. However, other features on the nacelle such as the cooling rack might block light output and should be taken into account when installing/mounting the light units. The CL-864 lights operate alternatively and therefore installation of these lights on opposite sides of the nacelle, so that the nacelle itself becomes a blocking feature, is not acceptable. Depending upon the diameter of the support mast, more than three CL-810 lights may be installed. For a lattice-work support mast, at least 4 CL-810 lights should be installed to give an unobstructed view.

    Information note 2:
    (effective 2019/12/15)

    The above standard does not address wind turbines of more than 315 m. For wind turbines of more than 315 m of overall height, additional marking and lighting may be required.
    (effective 2016/03/01)

    

    Text version – Figure 12-2: Lighting Wind turbines; Heights 150 m to 315 m

    Figure 12-2 contains two schematics which illustrate the application of lighting on windturbines of more than 150 m in height.

    The left schematic shows a horizontal windturbine having a mid-level of at least three CL-810 lights and two CL-864 lights installed on the nacelle; one operating and one standby. The nacelle lights are installed on top of each other so that they do not block the light output from each other. The mid-level lights are configured to flash at the same rate as the top nacelle lights.

    The right schematic is an orthogonal chart illustrating a typical installation for which a vertical blade is 1/2 the nacelle height. The x-coordinate is the overall height of the windturbine. The y coordinate is the height of the lights. From 0 m to 45 m the top light [on the nacelle] is a CL-810. From 45 m to 150 m, the top light is a CL-864. From 150 m to 315 m there are two CL-864 top lights one operating and one standby, and a mid-level of at least three CL-810 lights. The two CL-864 nacelle lights are installed on top of each other so that the light output of the operating light is not blocked by the standby light.

• (3) The provision of marking and lighting for wind turbines higher than 315 m is determined through means of an aeronautical assessment.
  (effective 2019/12/15)

12.4 Continued Illumination

The lighting provided for a wind turbine or wind farm is so designed such that it can draw power from the electrical grid for continued illumination even though the wind turbine on which it is mounted ceases operation.

Information note:

12.5 Temporary Lighting During Construction
(effective 2019/12/15)

• (1) In order to ensure conspicuity of turbines at night during construction, all turbines are lit with temporary lighting once they reach a height of 60 m or greater until such time the permanent lighting for the wind farm in total is turned on.

  Information note:

  Wind turbines are provided with permanent CL-864 lights spaced at a distance of approximately 900 m. This enables some of the wind turbines to not have lighting. The meaning of (1) is that temporary lighting is maintained on all wind turbines until such time as the permanent lighting for the total of the wind turbine is turned on.

• (2) As the height of the structure continues to increase, the temporary lighting is relocated to the uppermost part of the completed structure.

  Information note:

  For wind turbines of more than 150 m there is an intermediate level of flashing CL-810 lights. This level may be bypassed by the temporary lighting, as indicated in (2). The intermediate level of lighting is turned on at the time of completion of construction.

• (3) If practical, permanent CL-864 and CL-810 obstruction lights are installed and operated as construction progresses.
• (4) At least two CL-810 fixtures are used at each level, during the construction phase, where the structure intervenes. The lights are positioned to ensure that a pilot has an unobstructed view of at least one light. One CL-810 light is used when this lighting is clear of any blocking structure with exception of a wind turbine blade, if present.

12.6 MET Towers (meteorological towers)
(effective 2016/03/01)

MET towers that are used to measure the wind resource available for wind farms may present a hazard to aircraft engaging in low level flight for aerial application of pesticides and other products. As illustrated in Figure 12-3, MET towers that are 60 m or more in height comprise:

• (a) marker balls on the outer guy wires near the top of the tower;
• (b) a mast of the tower is painted in a banded pattern as stipulated in subsection 3.5(3); and
• (c) high visibility sleeves on the outer guy wires close to the anchor points, but at a height above the expected crop/vegetation canopy.

Information note 1:
(effective 2019/12/15)

Information note 2:
(effective 2019/12/15)

Text version – Figure 12-3: MET Tower Marking

Figure 12-3 has two schematics showing the marking of a MET [Meteorological] tower. The left-hand schematic shows a top view. The right-hand schematic shows a profile view. The marking is composed of a centre support mast painted in bands of orange and white. Near the top of the support mast, four orange marker balls are installed on the guy wires. Yellow sleeves are installed at the bottom of the guy wires and at a height above expected vegetation.

The Figure 12-3 does not show lighting as it is considered that the application is primarily for specialized low level flight [e.g. crop spraying] and that this activity occurs only during daytime.

Chapter 13 Obstruction Lighting Characteristics

13.1 Scope

• (1) Chapter 13 governs the signal characteristics of the lighting equipment required under this standard.
• (2) The context of this chapter is that obstacle lights are composed of multiple devices (i.e. Light Emitting Diodes (LEDs)).  Red obstacle lighting with designations CL810, CL864 and CL885 are to have additional devices that produce infrared (IR) light to make this obstacle lighting compatible with Night Vision Goggles (NVG) designed to MIL-STD-3009.  White obstacle lighting with designations CL865, CL856 and CL857 do not need additional infrared devices.
  (effective 2022/12/15)
• (3) Terminology:  For CL810, CL864 and CL885 light fixtures, the portion of the signal which is to be seen by the unaided eye is referred to as the “Visible portion” and the devices for this portion as the “Red” LEDS.  The infrared portion of the signal is referred to as the “IR portion” and the devices for this portion as the “IR” LEDS.  The term “light” refers to any emission within the Visible and infrared regions of the electromagnetic radiation spectrum.
  (effective 2022/12/15)

13.2 Visual Range and Intensity
(effective 2022/12/15)

• (1) Where acquisition distance [i.e. visual range] of an obstacle light is to be found, it is determined with use of Allard’s Law and transmissivity/visibility formula TV=0.05.  The illuminance threshold is 1000 mile candles [386 kilometer candle] [3.86*10-4 lux] for daytime operation and 2 mile candle [7.72 kilometer candle] [7.72 * 10-7 lux] for nighttime operation.  This applies only to the Visible portion of the light signal which has units of candelas.

13.3 Light Intensity Reduction (LIR) System
(effective 2022/12/15)

• (1) Where a Light Intensity Reduction (LIR) system (refer Chapter 16) is to be used, the IR portion of the signal (or separate IR fixture) is not reduced in intensity below the minimum intensity requirement in Table 13-5.

13.4 Operation
(effective 2022/12/15)

• (1) For CL810, CL864 and CL885 light fixtures the IR and Visible portions of the light signal are normally operationally ON in unison.

13.5 Monitoring - Failure Mode - Alarm Generation
(effective 2022/12/15)

• (1) Failure Alarm
  • (i) For CL865, CL866, CL856 and CL857 light fixtures which have only White LEDs, a failure alarm is generated when more than 25% of LEDs have failed.
  • (ii) For CL810, CL864 and CL885 light fixtures, a failure alarm is generated when more than 25% of Red LEDs and IR LEDs, in combination, have failed.
  • ((iii) Alternatively, for CL810, CL864 and CL885 light fixtures, where the Red LEDs and IR LEDs are separately accessible for monitoring, the failure alarm is generated when more than 25% of Red LEDs or more than 25% of IR LEDs have failed.
• (2) Decoupled:  For CL864 and CL885 light fixtures, failure of the IR portion of the signal, does not cause shutdown of the Visible portion of the signal.
• (3) In the case of tower application, for a tier of [level of] CL810 light fixtures, a failure alarm is generated upon occurrence of failure of any one CL810 light fixture within the tier of CL810 light fixtures.

13.6 Equipment Specification - Appendix B
(effective 2022/12/15)

• (1) Additional performance requirements are contained in Sections 3.3 and 3.4 of Appendix B of Standard 621:

13.7 Photometrics

• (1) The photometric output requirements of obstacle light units are in accordance with section 13.10 for Visible light to be seen by the unaided eye, and section 13.11 for IR light to be seen through NVG. Figures 13-2 and 13-3 illustrate the Visible light photometric requirements and IR photometric requirements.
  (effective 2022/12/15)

13.8 Photocell Control

• (1) Red and white obstruction lighting systems are operated by means of a control device adjusted so the lights are turned on and off and change intensity steps when the Northsky illuminance, on a vertical surface, transitions through day-to-twilight and twilight-to-night levels according to Tables 13-1 and 13-2.  Figure 13-1 illustrates how these settings define the operational durations of Day, Twilight and Night. (effective 2022/12/15)

Table 13-1:  Photocell Control Settings for Northsky Illuminance
(effective 2016/03/01)

Operational transition		Northsky illuminance range
from	to	from footcandles (lux)	to footcandles (lux)
day	twilight	60  (645.8)	35  (376.7)
twilight	night	5  (53.8)	2  (21.5)
night	twilight	2  (21.5)	5  (53.8)
twilight	day	35  (376.7)	60  (645.8)

Figure 13-1:  Photocell Settings
(effective 2022/12/15)

Text version – Figure 13-1: Photocell Settings

Figure 13-1 illustrates the photocell settings of Table 13-1 by means of a greyscale diagram in the form of a vertical column. Night operation is indicated as a dark grey section at the bottom, twilight as a light grey section at a mid point, and day operation as a lighter grey section at the top. It is intended that change from night to day occurs from the bottom upwards on the diagram and change from day to night is from the top downwards.

The transition from night to twilight is not instantaneous but is shown as a narrow cross-hatched band that applies to a Northsky illuminance change between 2 and 5 footcandles. The transition from twilight to day is shown as another narrow cross-hatched band that applies to a Northsky illuminance change between between 35 and 60 footcandles. Change from day to twilight to night is in the reverse direction through the transition bands.

Table 13-2:  Control settings
(effective 2022/12/15)

Light	Colour		Signal type		flash rate (fpm)		Nominal intensity (cd)		Minimum intensity (cd)
									Day	Twilight	Night
[1]	[2]	[3]		[4]		[5]		[6]		[7]	[8]
CL810	red	fixed		---		32		---		32	32
CL810F	red	flashing		20-40		32		---		32	32
CL856	white	flashing		40		270,000		200,000		15,000	1500
CL857	white	flashing		60		140,000		100, 000		15,000	1500
CL864	red	flashing		20-40		2000		---		1500	1500
CL865(e)	white	flashing		20-40		20,000		15,000		15,000	1500
CL866	white	flashing		60		20,000		15,000		15,000	1500
CL885	red	flashing		60		2000		---		1500	1500

13.9 Visible Light Characteristics
(effective 2022/12/15)

• (1)  The following tables apply to the Visible portion of the output signal.

Table 13-3: Light distribution for low-intensity obstacle lights [Figure 13-2]
(effective 2022/12/15)

Light Type	Signal type	Minimum intensity (a)	Min. Vertical Beam Spread (degrees) (c)	Vertical range (degrees)
				Lower limit	Upper limit
[1]	[2]	[3]	[4]	[5]	[6]
CL810	fixed	32 cd	10	+2.5°	+12.5°
CL810F	flashing	32 cd (b)	10	+2.5°	+12.5°

Notes for Table 13-3
(effective 2022/12/15)

Table 13-4a:  MINIMUM Effective intensities of flashing lights (a) [Figure 13-3]
(effective 2022/12/15)

Light Type	Nominal intensity	Min. intensity at vertical elevation angle (b)		Vertical beam spread (c)
		0° 0.75*[2]	-1° 0.5*[3]	Min. Beam spread (degrees)	Intensity 0.5*[3]
[1]	[2]	[3]	[4]	[5]	[6]
CL856	270,000	200,000	100,000	3°	100,000
CL857	140,000	100,000	50,000	3°	50,000
CL864	2000	1500	750	3°	750
CL865 (e)(f)	20,000	15,000	7500	3°	7500
CL866	20,000	15,000	7500	3°	7500
CL885	2000	1500	750	3°	750

Table 13-4b:  RECOMMENDED maximum effective intensities of flashing lights (a)(d)
(effective 2022/12/15)

Light Type	Nominal intensity	Intensity for vertical elevation angle (b)			Vertical beam spread (c)
		0° 1.25*[8]	-1° 0.75*[3]	-10° 0.03*[9]	Beam spread	Intensity 0.5*[3]
[7]	[8]	[9]	[10]	[11]	[12]	[13]
CL856	270,000	337,500	150,000	10,125	7°	100,000
CL857	140,000	175,000	75,000	5250	7°	50,000
CL864	2000	2500	1125	75	N/A	N/A
CL865 (e)(f)	20,000	25,000	11,250	750	N/A	N/A
CL866	20,000	25,000	11,250	750	N/A	N/A
CL885	2000	2500	1125	75	N/A	N/A

Collective notes for Tables 13-4a and 13-4b:
(effective 2022/12/15)

• (a) 360 degrees horizontal, except CL857 which may have 180 degrees coverage for the middle and bottom lights on the support structures of catenaries.  Effective intensity, as determined in accordance with Appendix B.
• (b) Elevation vertical angles are referenced to the horizontal when the light unit is levelled.
• (c) Beam spread is defined as the angle between points in a vertical plane where the actual measured intensity values are equal to 50% of the specified minimum intensity shown in column [3].
• (d) Maximum intensities are recommended.  Exceeding the maximum may result in residential complaint.
• (e) In the case of a rotating type CL865, one-third of the flash display is red in colour. e.g. WWRWWR.
• (f) In the case of a rotating type CL865, the intensity of the red flash is at least 0.15 of the white flash

13.10 Infrared [IR] Specification
(effective 2022/12/15)

Note:  This section pertains to the infrared component of the signal for red obstacle lighting.

Table 13-5. Infrared Specifications for LED CL810, CL864 and CL885 LED Obstacle Lights.
(effective 2022/12/15)

Light unit	Vertical Beam width (degrees)	Minimum Radiant Intensity mW/sr*	IR Wavelengths (nanometers)	Figure
[1]	[2]	[3]	[4]	[5]
CL810 & CL810(F)	≥ 10	≥ 4	800 to 900	13-2
CL864 & CL885	≥ 3	≥ 246	800 to 900	13-3

* milliwatts per steradian

Figure 13-2:   Visible light CL810 and CL810(F), Table 13-3 column [3] IR light CL810 and CL810(F), Table 13-5 column [3]
(effective 2022/12/15)

Text version – Figure 13-2

The Figure 13-2 is an orthogonal chart. The vertical axis is positioned on the left-hand side and is in degrees from minus 10 degrees upwards to plus 20 degrees. The horizontal axis, beginning at zero degrees on the vertical axis, is for percent of specified minimum intensity from zero to 100 percent.

The Figure 13-2 illustrates the photometric requirement for the visible and infrared output of the low intensity CL810 steady burning and CL810(F) flashing lights. This is shown as a reclined rectangle whose width is from plus 2.5 degrees to plus 12.5 degrees. The length extends to the right at 100%. Since the required distribution for the visible and infrared outputs are to be similar, only one rectangle is shown. The visible output is from Table 13-3, column 3 where 100 percent is 32 candela and the infrared output is from Table 13-5, column 3, for which 100 percent is 4 milliwatts per steradian.

Figure 13-3: Visible light CL856, CL857, CL864, CL865, CL866, CL885, Table 13-4a column [3] IR light CL864, CL885, Table 13-5 column [3]
(effective 2022/12/15)

Text version – Figure 13-3

The Figure 13-3 is also an orthogonal chart. The left-hand vertical axis is in degrees from minus 10 degrees upwards to plus 15 degrees. The horizontal axis, beginning at zero degrees on the vertical axis, is for percent of specified minimum intensity from zero to 100 percent.

The Figure 13-3 illustrates the photometric requirement for medium and high intensity lights for the visible output of CL856, CL857, CL864, CL865 and CL866 lights, and for infrared output of CL864 and CL885 lights, which are red in colour. Because the manner of specification for medium and high intensity lights, and that the distribution of the infrared output is to be similar to the visible output, only one bell-shaped curve is given as the example. The curve is shown as reclined along the horizontal axis of the chart. Specification points are shown at 50 percent at minus one degree and 100 percent at zero degrees. The values related to these percentages are from Table 13-4a, column 3, for visible output and Table 13-5, column 3 for infrared output. Figure 13-3 also indicates the location of points at 50 percent for measurement of minimum beam spread.

Chapter 14 Maintenance

14.1 Scope

Chapter 14 governs the maintenance of marking and lighting required under this Standard.

14.2 Marking and Markers
(effective 2016/03/01)

• (1) The surfaces of a building, structure or object required to be marked with paint, are repainted when the colour changes noticeably or when its effectiveness is reduced by scaling, oxidization, chipping or layers of contamination.

  Information note:

  In-Service Aviation Orange Colour Tolerance Charts are available from private suppliers for determining when repainting is required. The colour should be sampled on the upper half of the structure, since weathering is greater there.

  

  Text version – Figure 14-1: In-service Aviation Orange Colour Tolerance Chart

  Figure 14-1 is a photograph of an aviation orange colour tolerance chart. The chart is similar to a bristol board file folder. Each of the two pages has a viewing window or opening through which the actual orange paint marking is viewed on a tower at site.

  Around each window are nine orange colour chips that vary in chromaticity. The user compares the actual paint marking as seen through this window against the colour chips.

  One page is for light limit colours of maximum reflectance and the other page is for dark limit colours of minimum reflectance.

  By comparing the actual paint to the colour chips of the chart, the owner can determine when it is necessary to repaint the obstacle. The tower paint is assessed only in regard to orange. A chart for aviation white has not been developed.

• (2) Powerline markers are inspected at least once a year to verify presence and continued visibility.
  (effective 2016/03/01)

14.3 Lighting

• (1) Operating Voltage

  To ensure proper candela output:

  • (a) for light units with incandescent lamps, the voltage provided to the lamp socket shall be within ± 3 percent of the rated voltage of the lamp; or
  • (b) for light units with strobe [capacitor discharge] lamps, the input voltage to the power supply shall be within ±10 percent of rated voltage of the power supply.
• (2) Lamp Replacement
  • (a) A lamp in a light unit is replaced immediately upon failure or after being operated for not more than 75 percent of its rated life.
  • (b) A flashtube in a light unit is replaced:
    • (i) immediately upon failure, or
    • (ii) when the peak effective intensity falls below specification limits, when the fixture begins skipping flashes or at the manufacturer's recommended intervals, whichever occurs first.
• (3) Fixture Lenses

  Owing to the effects of harsh environments, a beacon lens is visually inspected for ultraviolet damage, cracks, crazing, dirt build up or similar forms of degradation, to ensure that the required certified light output has not been adversely affected.

14.4 Removal of Obscuring Effects

Regular inspection takes place and remedial action undertaken to ensure that effects, such as the growth of vegetation, do not obscure the pilot's view of any portion of marking or lighting displayed pursuant to this Standard.

Chapter 15 Aircraft Detection System (ADS)

15.1 Scope

• (1) Chapter 15 governs Aircraft Detection Systems (ADS) which are used to turn on obstruction lighting systems upon detection of an approaching aircraft. The system is sensor based and can detect and analyze the flight path [position, altitude, heading and ground speed] of an aircraft so as to determine the possibility of potential collision with an object. If the flight path is such that the aircraft may impact the obstacle, then the obstacle lights are turned on and an audio signal may be transmitted. The purpose of the system is to enable the lighting to be off when not needed [absence of aircraft] and thereby reduce energy consumption and minimize cause for complaint from local residents.
  (effective 2016/03/01)
• (2) The means of detection is not dependent upon equipment on the aircraft [e.g. a transponder].
  (effective 2016/03/01)

15.2 Impact Boundary

• (1) The impact boundary is a 3-dimensional boundary around the obstacle approved by the Minister, so as to establish the distance [in terms of seconds] from the location of the detected aircraft to a point of impact on this boundary.
• (2) The impact boundary is at a horizontal distance of 30 m to 60 m from the actual physical sides of the obstacle, as shown in Figure 15-1.
  (effective 2016/03/01)

  Information note:

  An impact boundary for a catenary is shown in Figure 15-1. Different shapes of impact boundary may be required for different obstacles. In the case of lengthy or large area objects, more than one ADS sensor may be required.
  (effective 2016/03/01)

• (3) In vertical dimension, the impact boundary extends 60 m above the highest portion of the obstacle.

15.3 Operation

• (1) The system has two primary functions: to turn on the obstacle lights and to emit an audio signal. These functions are performed with respect to the detection of the aircraft within a specified minimum flight time to the impact boundary for both a heading directly towards the impact boundary as well as a potential manoeuvre towards the impact boundary.

• (2) The system has the following minimum timings for light and audio signal activation with respect to the speed of the aircraft and time from the impact boundary:

  Table 15-1: Time to Impact Boundary
  (effective 2016/03/01)

  Aircraft speed (knots)	Aircraft speed (metres/second)	Time to Impact Boundary (seconds)
  90	46.3	30
  120	61.7	30
  165	84.9	30
  180	92.6	30
  250	128.6	30

• (3) Potential Manoeuvre to Impact Boundary

  The following addresses the case of aircraft that are not on a direct flight path to impact, but have the potential for impact.

  • (a) The ADS detects and causes light and audio signal activation per 15.3.2 for aircraft flying in the horizontal plane that would have a potential of impact if it were to conduct a turning manoeuvre of up to 2g. Refer to Figure 15-3.
  • (b) The ADS detects and causes light and audio signal activation per 15.3.2 for aircraft flying in the horizontal plane that would have a potential of impact if it were to conduct a descent of rate of up to 2.5m/s [500  ft per minute]. Refer to Figure 15-3.

  (4) Lighting

  • (a) Once the lighting is activated upon aircraft detection, the lighting is maintained on for a period of at least 60 seconds.
  • (b) The lighting for use with ADS is of a design such that it will provide full intensity within 2 seconds of activation.

  (5) Audio Signal

  • (a) The provision of an audio signal is required for catenary crossings where obstacle lighting is on the support structures. The provision of an audio signal for extensive objects such as a wind farm is determined on a site specific basis.
    (effective 2016/03/01)

  • (b) The audio signal consists of a 3 note chime followed by a worded message indicating the type of obstacle as determined locally. For example, for a catenary crossing, the term "power line" may be used. The signal is repeated a total of 6 times for slow speed aircraft and 3 times for high speed aircraft [>250 knots], for a total duration of 12 seconds and 6 seconds respectively.
  • (c) The audio signal is limited in range so as to not interfere with other non- ADS broadcasts. The limitation of range is tested using standard General Aviation VHF radio and antenna equipment while the ADS VHF transmitter is transmitting a continuous test signal; range limit is where the perceived signal quality comes below level 4.

    Information note 1:

    A limited range represented by a volume of space defined by a cylinder centred on the ADS unit with a radius of 7 km and height of 1.8 km, is recommended.

    Information note 2:

    In the radio terminology, the quality of the radio signal is rated on a scale from 1 through 5, where 1 is the worst (unreadable) and 5 is the best. A quality of 4 is fully readable, when below 4 the audio signal is degraded below an acceptable level.
    (effective 2016/03/01)

  • (d) The audio signal is broadcast simultaneously with light activation on multiple frequencies in the VHF band over the range of 118 to 136 MHz. The frequencies are selected as appropriate for local requirements.
    (effective 2016/03/01)

  (6) Warning Zones

  Information note:

  The ADS may be considered to establish "warning zones" around the obstacle based upon the timing for light activation and audio signal transmission in relation to the impact boundary. The warning zone, therefore, extends outward from the impact boundary to the detected aircraft. Since light activation and transmission of the audio signal [if provided] occur simultaneously, the audio warning zone and the light activation warning zone are equal in dimension.
  (effective 2016/03/01)

  • (a) If the aircraft enters the audio signal warning zone, an audio signal is transmitted. If the aircraft remains within this zone no additional audio signals are provided. A new signal will be provided, if the aircraft leaves the zone and then re-enters.
  • (b) If the aircraft enters the light activation warning zone, the lights are turned on and will continue to be illuminated for the period specified in section 15.3.4. If the aircraft remains within this zone beyond the specified period, the lights will turn off. The lights will be re-activated, when the aircraft leaves the zone and then re-enters.

  (7) Frequencies

  • (a) Audio signal radio broadcasts comply with applicable Innovation, Science and Economic Development Canada guidelines and permit requirements.
    (effective 2016/03/01)
  • (b) If radar is used, the radar frequencies are selected so as to not cause interference with other radar operations.
    (effective 2016/03/01)

15.4 Monitoring

The ADS has continuous electronic monitoring to detect failure of the major components.

• (a) Sensor or Communications Failure: The occurrence of failure of the sensor or of the communication link to the lights cause the lighting to be turned on continuously, the audio signal deactivated and an alarm given to a 24 hour staffed station. There is provision for immediate issuance of a NOTAM from this station. The communication status and operational status of the system are confirmed at least once every 24 hours.
  (effective 2016/03/01)
• (b) Obstruction Lights Failure: If a light outage occurs, the audio warning function remains active, the monitoring station is notified and a NOTAM issued. Corrective action is taken as soon as possible to restore the lights.

15.5 Self Test

Unless the system has been activated at least once within a 24 hour period by aircraft, the system is activated for self test at least once within a 24 hour interval to verify the operational status.

15.6 Sensor Unit Backup Power Supply
(effective 2016/03/01)

The sensor unit is provided with a battery backup supply having a capacity for at least 24 hours of operation, to enable communication to turn on the lights in case of external power supply failure.
(effective 2016/03/01)

15.7 Submission of Application for Use

The design and function of each control device is described in the ADS application. The control device description includes: functionality, selectable features, program modification, maintenance actions, failure/monitoring provisions and any reporting functions. The reportable functions are described and the methodology detailed for accumulating information.

15.8 Commissioning Test

The ADS installation is subject to a commissioning test to verify:

• (a) the required performance of the system,
• (b) absence of any interferences of a sensor unit based upon radar with other radars in the area, and
  (effective 2016/03/01)
• (c) that the audio does not present a hazard to other aircraft communications not in proximity to the obstruction hazard.

  

  Text version – Figure 15-1: Catenary Crossing - Plan View

  Figure 15-1 illustrates a plan view of the impact boundary for an obstacle that is to be provided with an ADS [Aircraft Detection System]. The ADS is to detect an aircraft and turn the lights ON and also emit an audible warning signal 30 seconds prior to potential impact.

  It is important to note that the impact boundary does not represent the detection distance. The aircraft is detected outside and 30 seconds prior to the impact boundary. The distance of detection is dependent upon the aircraft speed which is determined by the ADS.

  Figure 15 1 is for a catenary crossing over a river. In plan view, the impact boundary is a narrow rectangle that includes the support structures having obstacle lights on each side of the river. The rectangle has a horizontal distance of 30 m to 60 m outside of the obstacle lights. In plan view, the impact boundary has a width of 60 m to 120 m and a length which is the distance of separation of the support structures over the river plus 60 m to 120 m.

  Figure 15-1 shows an impact boundary for a catenary crossing. The text of Standard 621 mentions that impact boundaries of other shape would be used for different types of obstacles.

  Figure 15-1 shows a cross section cut line for the impact boundary and reference is made to Figure 15-2.

  

  Text version – Figure 15-2: Catenary Crossing - Profile View

  Figure 15-2 shows the cross section indicated in Figure 15-1 for the impact boundary. The impact boundary is shown in Figure 15-2 as a volume of space defined in relation to the height and length of the obstacle.

  The impact boundary extends vertically from the river to 60m above the highest point of the obstacle which in this case is the support structure on the left-hand side of the river. The highest tower is shown in the figure as 260 m AGL and therefore the top of the impact boundary is at 260 m plus 60 m equals 320 m.

  The impact boundary is shown as extending beyond the towers. A dimension for this extension is not indicated, but is the 30 m to 60 m margin shown in Figure 15-1.

  

  Text version – Figure 15-3: Potential Turning/Descent Manoeuvres

  Figure 15-3 has three schematics illustrating a volume of space which is the impact boundary and possible entry of aircraft into the impact boundary from above and from the side. These are aircraft which, if not doing a manoeuvre to turn or descend, would miss the impact boundary entirely. When the ADS detects the aircraft, it also determines the manoeuvre.

  The first schematic shows the impact boundary as Figure 15-2.

  The second schematic is a side view showing an aircraft flying in the horizontal plane above the impact boundary. The obstacle lights are turned ON should the aircraft conduct a manoeuvre to descend at a rate of up to 2.5 m/s.

  The third schematic is a plan view showing an aircraft flying to the side of the impact boundary. The lights are turned ON should the aircraft conduct a manoeuvre to turn at a rate of up to 2 g.

Chapter 16 – Light Intensity Reduction (LIR) System

(effective 2021/08/06)

16.1 Scope

• 16.1.1  Chapter 16 governs the Light Intensity Reduction (LIR) system intended as a means to reduce the intensity of obstacle lighting according to visibility measurements.
• 16.1.2  The LIR system controls the lighting for reduced intensity only for the Night period of operation.  During the Twilight period, the lighting is set at 100% intensity.

Information Note:  Refer article 13.4 for photocell settings for Day, Twilight and Night.
(effective 2021/08/06)

• 16.1.3  For wind turbines of more than 150 m in overall height, the LIR system is not applied to CL810 lights as installed at the mid-point of the mast.

(effective 2021/08/06)

16.2 Installation

• 16.2.1  Visibility sensors are installed on the nacelle of selected wind turbines.
• 16.2.2  A wind farm is equipped with a minimum of 2 visibility sensors.

Information Note:  A wind farm is defined as that having at least 3 wind turbines (refer article 1.1 Definitions).  A wind farm of minimum size might have all wind turbines within a circle of 1500 m. Such wind farm, however, would have not less than 2 visibility sensors.  This standard is not intended to mean that a wind farm of any size might have 2 visibility sensors.
(effective 2021/08/06)

• 16.2.3  Spacing:  The distance between a wind turbine with a visibility sensor and wind turbines without a visibility sensors is not more than 1500m +10%. [refer Figure 16-1].
• 16.2.4  The visibility sensor shall conform to the specification given in ICAO Doc 9837, Manual on Automatic Meteorological Observing Systems, Appendix B.

(effective 2021/08/06)

16.3 Control System

• 16.3.1  The control system reduces the intensity of installed CL864 red obstacle lights according to the following criteria:

Table 16-1.  Intensity Reduction according to Visibility (Night only)
(effective 2021/08/06)

Visibility	Light Setting	Intensity (nominal)
x ≤ 5 km	100%	2000
5 km < x ≤ 10 km	30%	600
10 km < x	10%	200

• 16.3.2  The control system is remotely accessible so that it is possible to reset the lighting to maximum setting of 100%, should this be necessary.
• 16.3.3  The most unfavorable [lowest] visibility value obtained for any sensor is used to determine the light intensity setting for the entire wind farm.  For example, if the wind farm has 10 sensors with 9 reporting a visibility of 11 km and 1 reporting a visibility of 6 km, the system controls the lighting to the setting for 6 km or 30%.
  • (1)  The visibility sensors report their visibility measurement to the controller at least once per minute.
  • (2)  Should the report of visibilities indicate a change of setting, the change occurs within 60 seconds.
• 16.3.4  If a particular sensor fails to report to the control system, the absence of report is taken to be the most unfavourable (e.g. less than 5 km) and this causes the obstacle lighting to be set at 100% intensity.

(effective 2021/08/06)

16.4 Light unit failure

• 16.4.1  When there is failure of a light unit within the wind farm, the required NOTAM is issued, but the LIR system continues to operate normally so that it is capable of reducing the intensity of the remaining light units in accordance with measured visibility.

(effective 2021/08/06)

16.5 Data Record

• 16.5.1  Data on the intensity change with corresponding visibility measurement of each individual sensor within the LIR system is recorded.  The record is retained for a period of at least 4 weeks.
• 16.5.2  The data record includes a date/time stamp indicating when the system requested a change in light intensity level.  The records also show a date/time stamp where the lights are confirming what actual intensity level they are operating at.

(effective 2021/08/06)

16.6 Test Device

• 16.6.1  The LIR system is provided with a means to in-situ verify or re-calibrate each visibility sensor in relation to the required dimmed intensity level specified in Table 16-1.

Information note:  The visibility sensors should be tested at least once per year, or more frequently in areas where the atmosphere may readily contaminate the sensor.
(effective 2021/08/06)

Figure 16-1. Application of visibility sensors for a wind farm
(effective 2021/08/06)

Text version for Figure 16-1: Application of visibility sensors for a wind farm

Figure 16-1 is a plan view of how windturbines without a visibility sensor are located in relation to windturbines with a visibility sensor. The windturbines are represented as small circles. In this figure, the circles for windturbines with visibility sensor are white in colour; those without visibility sensor are black in colour. Larger circles of 1500 meter radius are drawn around the windturbines with visibility sensor. In this example, there are 14 large circles each centred on a windturbine having a visibility sensor. To meet the criteria of this chapter, all of the windturbines without visibility sensor are to be found inside at least one of the 1500 meter circles. That is, a maximum distance of 1500 meters from a windturbine with a visibility sensor. If some are not, the designer must do a new arrangement to ensure that all are contained. This might involve a new distribution of visibility sensors over the windfarm or require the installation of an additional visibility sensor. A tolerance of +10% is applied for those windturbines that are marginally outside a 1500 meter radius circle.

Appendix A - Contact Information

Transport Canada Civil Aviation Regional Offices

Region	Postal Address	Email Address
Pacific	Transport Canada Suite 620, 800 Burrard St. Vancouver, British Columbia V6Z 2J8	aviation.pac@tc.gc.ca
Prairie and Northern for Alberta, Saskatchewan, Manitoba, Yukon Nunavut and NWT	Transport Canada 1100, 9700 Jasper Avenue Edmonton, Alberta T5J 4E6	aviation.pnraaf-rpnfea@tc.gc.ca
Ontario	Transport Canada 4900 Yonge Street, 4th Floor Toronto, Ontario M2N 6A5	aviation.ont@tc.gc.ca
Quebec	Transport Canada 700 Leigh Capréol Dorval, Quebec H4Y 1G7	csva-vsca@tc.gc.ca
Atlantic for Nova Scotia, New Brunswick, Prince Edward Island and Newfoundland and Labrador	Transport Canada P.O. Box 42 Moncton, New Brunswick E1C 8K6	aviation.atl@tc.gc.ca

NAV CANADA

If there is a failure of obstacle lighting and it is to be reported through means of a NOTAM, one should contact the NAV CANADA Flight Information Centre in which the object is located.

Nav Canada Flight Information Centre (FIC)

Appendix B

Specification for Obstruction Lighting Equipment

Foreword
(effective 2016/03/01)

1. Purpose. This appendix to Standard 621 contains Transport Canada specifications for obstruction lighting equipment.

2. Effective date. Effective 6 months after publication of this specification.

3. Cancellation. Appendix B, Specification for Obstruction Lighting Equipment , dated 31 December 2011 is canceled.

4. Principal changes

• (a) Section 2.0. Removal of reference to Institute of Electrical and Electronics Engineers (IEEE) publications and Illuminating Engineering Society (IES) publications
• (b) Section 3.3.3. Addition of white colour boundaries for Incandescent Xenon and LED sources
• (c) Section 3.3.3.1. Removal of the section since it is a statement of non-requirement for daytime colour
• (d) Paragraph 3.3.4 (b). Clarification of aiming accuracy of ± one degree
• (e) Section 3.3.5.2.2. Added "the system and individual light unit" to correspond with 3.3.5.1.1(d)
• (f) Section 3.3.7. Removal of section for reason that there is no test criteria and it does not relate to the lighting display
• (g) Section 3.4.1. Removal of duplication of effective intensity formula
• (h) Section 3.4.2, Table 1. In the English edition, correction of microseconds to milliseconds
• (i) Section 4.1. Removed (d) because it is obvious
• (j) Section 4.10. Added verification of monitoring capability

5. Comments or suggestions for improvements to this appendix should be sent to:

Chief, Flight Standards
Transport Canada
ATTN: AARTA
330 Sparks Street,
Ottawa, Ontario, K1A 0N8
Canada

1.0 Introduction

1.1 Scope

This specification sets forth design and qualification test criteria for obstruction lighting equipment used to increase conspicuity of structures to permit early obstruction recognition by pilots.

1.2 Equipment Classification

Light	Intensity type	colour	Flash rate	Flash Cycle Duration
CL-810	low	red	steady burning	not applicablen/a
CL-856	high	white	40 fpm	1500 ms
CL-857	high	white	60 fpm	1000 ms
CL-864	medium	red	20 to 40 fpm	3000 to 1500 ms
CL-865	medium	white	40 fpm	1500 ms
CL-866	medium	white	60 fpm	1000 ms
CL-885	medium	red	60 fpm	1000 ms

fpm = flashes per minute
ms = milliseconds

2.0 Reference documents

2.1 General

It is intended that the following reference documents be used in conjunction with this document:

2.2 Transport Canada

Standard 621 - Obstruction Marking and Lighting

2.3 Federal Aviation Administration (FAA) Advisory Circulars (ACs)

AC 70/7460-1 Obstruction Marking and Lighting

AC 150/5345-43 Specification for Obstruction Lighting Equipment
(effective 2016/03/01)

Information note:

2.4 Military Standards and Specifications

MIL- STD-810F Environmental Engineering Considerations and Laboratory Tests

MIL-C-7989 Cover, Light-Transmitting, for Aeronautical Lights, General Specification for

2.5 International Civil Aviation Organization (ICAO)

Annex 14 Volume 1, Aerodrome Design and Operations

2.6 Document Sources
(effective 2016/03/01)

Copies of military standards and specifications may be obtained from:

DAPS/DODSSP
Building 4, Section D
700 Robbins Avenue
Philadelphia, PA 19111-5094

Tel: (215) 697-2179
Website: dodssp.daps.dla.mil

Copies of ICAO documents may be obtained from:

ICAO, Document Sales Unit
999 University Street
Montreal, Quebec, Canada H3C 5H7

Tel: (514) 954-8022
email: sales@incao.int
Website: www.icao.int

3.0 Equipment Requirements

3.1 General

This section addresses environmental, design, and photometric requirements for obstruction light equipment. Criteria for selecting the proper obstruction lighting equipment, installation tolerances, and administrative information are in Standard 621, Obstruction Marking and Lighting.

3.2 Environmental Requirements

Obstruction lighting equipment is designed for continuous operation under the following conditions:

• (a) Temperature:
  • Storage/shipping: -55 degrees Celsius to +55 degrees Celsius
  • Operating: -40 degrees Celsius to +55 degrees Celsius
• (b) Humidity: 95 percent relative humidity.

• (c) Wind: Wind speeds up to 240 kilometres per hour.

• (d) Wind-blown Rain: Exposure to wind-blown rain from any direction.
• (e) Salt Fog: Exposure to salt-laden atmosphere.
• (f) Sunshine: Exposure to solar radiation.

3.3 Design Requirements

3.3.1 Light Unit

• (a) Materials used within the light unit are selected for compatibility with their environment.
• (b) All plastic lens parts (including gaskets), that are exposed to ultraviolet radiation or ozone gas do not change colour, crack, check, disintegrate, or be otherwise degraded (photometry remains compliant).
• (c) Each light unit is an independent unit and flashes at the specified intensity or at its highest intensity when control signals are absent.

3.3.2 Light Covers

• (a) Light-transmitting covers for light units are per the requirements in MIL-C-7989.
• (b) If plastic covers are used, they are resistant to checking, crazing, or colour changes caused by ultraviolet radiation or ozone gas exposure.
  (effective 2016/03/01)

3.3.3 Light Colours

The aviation red is per ICAO Annex 14, Volume 1, Appendix 1, Colours for Aeronautical Ground Lights , at operating temperature within the following chromaticity boundaries:
(effective 2016/03/01)

• (a) Colour Red

  purple boundary	y = 0.980 - x
  yellow boundary	y = 0.335

• (b) Colour White (incandescent and Xenon)
  (effective 2016/03/01)

  blank space	1st equation	2nd equation
  Yellow boundary	x = 0.500	blank space
  Blue boundary	x = 0.285	blank space
  Green boundary	y = 0.440	y = 0.150 + 0.640x
  Purple boundary	y = 0.050 + 0.750x	y = 0.382

• (c) Colour White (LED)
  (effective 2016/03/01)

  Yellow boundary	x = 0.440
  Blue boundary	x = 0.320
  Green boundary	y = 0.150 + 0.643x
  Purple boundary	y = 0.050 +0.757x

3.3.4 Aiming (for CL-856 and CL-857)

• (a) Light units have a method for adjustment of the vertical aiming angle between 0 and +8 degrees.
• (b) A spirit level or other device is provided as part of each light unit for setting the vertical aiming angle of the light beam with an accuracy of ± degree.

3.3.5 Control Unit

3.3.5.1 White Flashing Obstruction Lighting Systems

• (a) The control unit shall set the system's flash rate, intensity and sequence and shall be capable of controlling light units up to a distance of 762 m.
• (b) If the control unit or control wiring fails, the light units continue to flash at the flash rate indicated in Table 1.
• (c) Failure of an intensity step change circuit shall cause all light units to remain operating at their proper intensity or alternatively to operate at the high intensity step.

3.3.5.1.1 Monitoring.

• (a) Each light unit is monitored for FLASH/FAIL status.
• (b) FAIL status is defined as either of the following conditions: unit misses four or more consecutive flashes; unit flashes at wrong intensity step during day operation or failure of the continuous movement of the rotating device for rotating type flashing lights.
• (c) Monitoring is fail safe (i.e. active signals for FLASH and absence of signals for FAIL).
• (d) There is a provision to permit connection to a remote alarm device (supplied by others or as an option) to indicate the system and individual light unit FLASH/FAIL status.

3.3.5.1.2 In addition to the above:

• (a) The control unit displays the status of each light unit.
• (b) An intensity control override switch is also mounted in the enclosure to manually control light intensity during maintenance or in the event of a photoelectric control malfunction.

3.3.5.2 Red Flashing Obstruction Lighting Systems

• (a) The control unit sets the system flash rate and flash sequence. Failure of the flashing circuit causes the light units to energize and operate as steady burning lights.
• (b) An override switch is mounted on the control unit to manually control the lights during maintenance or in the event of a lack of a photoelectric control signal.
• (c) To ensure proper operation, all flashing red obstruction lights, inclusive of any associated system steady burning red lights, are certified with a control unit whether internal or external to the lighting unit.

3.3.5.2.1 Dual Lighting Systems

• (a) The control unit may be a separate unit or incorporated as part of either the white or red obstruction light control unit.
• (b) The control unit sets the operating mode for each light unit in the system.
• (c) Outage of one of two lamps, or any failure in the device that causes a reduction in intensity of the horizontal beam or results in an outage in the uppermost red beacon (CL-864 unit) or outage of any uppermost red strobe, cause the white obstruction light system to operate in its specified "night" step intensity.
• (d) At no time should both red and white systems be on simultaneously.

  Note: : This does not apply to a rotating type CL-865 which produces a WWRWWR signal. W = White; R = Red.

• (e) An override switch is mounted on the control unit to manually control the operating mode of the system during maintenance or in the event of a lack of a photoelectric control signal.

3.3.5.2.2 Monitoring

• (a) Each separate CL-864 light unit and each tier of CL-810 light units is monitored for FLASH/FAIL status.
• (b) "FAIL" is defined as outage of any lamp in a CL-864 light unit, outage of any one lamp in a tier of CL-810 light units, or failure of a flasher (steady on and/or total) for a CL-864 light unit.
• (c) Monitor signals are fail safe (i.e., active signals for FLASH and absence of signals for FAIL).
• (d) There is a provision to permit connection to a remote alarm device, (supplied by others or by the light manufacturer) to indicate the system and individual light unit FLASH/FAIL status.
  (effective 2016/03/01)

3.3.6 Input Voltage

• (a) The obstruction lighting equipment is designed to operate from the specified input voltage ±10 percent.
• (b) Incandescent lamps are operated to within ±3 percent of the rated lamp voltage to provide proper light output.

3.3.7 Optional Arctic Kit

Light systems may be offered with an optional arctic kit to enable operation in temperatures below -40 degrees Celsius.

3.4 Performance Requirements

3.4.1 Photometric

• (a) The light units meet or exceed the minimum photometric requirements found in Standard 621.
  (effective 2016/03/01)
• (b) The effective intensity for single pulse flashing lights is calculated per the following formula:
  (effective 2016/03/01)

  

  Text version – 3.4.1 Photometric

  The first equation in 3.4.1 is used to determine the effective intensity of a flashing light. This equation is referred to as the Blondel-Rey equation. The effective intensity is defined as the condition for which the flash is perceived by human vision as having an equivalent effect as a steady burning light emitting the same value of intensity. The eye evaluates light output in terms of quantity per time and this aspect is contained within the equation.

  The equation is composed of a numerator and denominator. The numerator expresses an integration of the light output of the flash over a time period of t₁ to t₂. This is the quantity of light. The denominator is the time period of t₁ to t₂ plus a factor which is associated with the image retention and which by convention is assigned a value of 0.2 seconds. Thus the formula divides a quantity light in a flash which occurs over a specified time period, by a longer time period that includes an associated eye response time. The result is quantity per time which is the effective intensity. The times t₁ and t₂ are the beginning and end of that part of the flash when the instantaneous value of intensity exceeds the effective intensity. Therefore the solution of the formula not only solves for the effective intensity but also the selection of times t₁ and t₂ which maximizes the value of effective intensity I_e. Since there are two unknowns, the solution is normally found through repeated calculation.

  Where:

  I_e

  = Effective intensity (Candela)

  I

  = Instantaneous intensity (Candela)

  t₁ , t₂

  = Times in seconds of the beginning and end of that part of the flash when the value of I exceeds I_e.This choice of the times maximizes the value of I_e.

• (c) For discharge type flashing lights, the equipment provides the specified light output at the specified temperature extremes as the input voltage simultaneously varies by ±10 percent from nominal.
• (d) The light intensity and beam distribution requirements for obstruction lighting equipment are specified in Chapter 13.
• (e) All intensities listed are effective intensities (except steady-burning red obstruction lights) measured at the flash rate specified in Table 1. All incandescent lights will be tested as steady burning lights.
• (f) The frequency of the pulses is not less than 50 Hz and the interval t^A- t₁ does not vary by more than ±5% from the nominal value from pulse to pulse over the simultaneous extremes of temperature and input voltage.
• (g) The effective intensity for multiple pulse flashes as used in strobe lights is calculated by:

  

  Text version – 3.4.1 Photometric

  The second equation in 3.4.1 is similar to the first equation in that it calculates effective intensity. The difference is that this second equation takes into consideration that the "flash" is actually composed of multiple pulses or a short burst of flashes which are visually evaluated as single flash. That is, the pulses occur close enough together that they tend to merge together. The equation, therefore, has a numerator which is the sum of integrations of individual pulses divided by the total time period plus 0.2 seconds to account for the image retention of the eye, as is the case for the first equation.

  Where:

  I_e

  = Effective intensity (Candela)

  I

  = Instantaneous intensity (Candela)

  t₁ , t₂

  = Times in seconds of the beginning and end of the first pulse flash when the value of I exceeds I_e. This choice of the times maximizes the value of I_e.

  t₃ , t₄

  = Times in seconds of the beginning and end of the second pulse flash when the value of I exceeds I_e. This choice of the times maximizes the value of I_e.

  t_n-1 , t_n

  = Times in seconds of the beginning and end of the last pulse flash when the value of I exceeds I_e. This choice of the times maximizes the value of I_e.

3.4.2 Flash Duration

Flash characteristics are defined in Table 1.

Table 1: Flash Duration

Type	Intensity	Intensity Step	Flash rateFootnote (1)	Flash DurationFootnote (2)
CL-856	high	day & twilight	40 fpm	less than 200 ms
		night	40fpm	between 100 and 250 ms
CL-857	high	day & twilight	60fpm	less than 200 ms
		night	60 fpm	between 100 and 250 ms
CL-864	medium	night	20-40 fpm	1/2 to 2/3 of flash period if incandescent lighting Footnote (note 3), and between 100 and 2/3 of flash cycle if other light source.
CL-865	medium	day & twilight	40 fpm	less than 200 ms
		night	40 fpm	between 100 and 2/3 of the flash cycle
CL-866	medium	day & twilight	60 fpm	less than 200 ms
		night	60 fpm	between 100 and 2/3 of the flash cycle
CL-885	medium	night	60 fpm	1/2 to 2/3 of flash period if incandescent lighting (note 3), and between 100 and 2/3 of the flash cycle if other light source.

fpm = flashes per minute
ms = milliseconds
(effective 2016/03/01)

3.4.3 System Flashing Requirements

3.4.3.1 Simultaneous Flashing Systems

All obstruction lights in systems composed of either CL-864 light units or CL-856 and/or CL-865 light units flash within 1/60 of a second of each other.

3.4.3.2 Sequenced Flashing Systems

• (a) Catenary support structure systems composed of CL-857, CL-866, or CL-885 light units have a sequenced flashing characteristic.
• (b) This system consists of three lighting levels on or near each supporting structure. One light level is near the top, one at the bottom or lowest point of the catenary, and one midway between the top and bottom.
• (c) The flash sequence is middle, top, and bottom.
• (d) The interval between top and bottom flashes is about twice the interval between middle and top flashes.
• (e) The interval between the end of one sequence and the beginning of the next is about 10 times the interval between middle and top flashes.
• (f) The time for the completion of one cycle is one second (±5 percent).

3.4.4 Intensity Step Changing

3.4.4.1 White Obstruction Lights

Refer Standard 621 for photocell settings for day, twilight and night operation.

3.4.4.2 Red Obstruction Lights

Refer Standard 621 for photocell settings for night operation.

4.0 Equipment Qualification Requirements

4.1 Qualification Tests - General

• (a) Qualification tests are conducted on the light unit in the following order:
  • (i) Initial photometric test, per section 4.2;
  • (ii) Environmental tests, per sections 4.3, 4.4, 4.5, 4.6, 4.7, 4.8 and 4.9 (in any order);
  • (iii) 1000 hours of continuous operation, per section 4.10;
  • (iv) System Operational Test, per section 4.10; and
  • (v) Sampling Photometric Test, per section 4.2.
• (b) Sample photometric and system operational tests are conducted after completion of all environmental tests.
• (c) The same unit(s) is used throughout the tests.
• (d) The tests may be run on the control unit, power supply, and a single light unit, with a simulated load replacing the other light units.
• (e) Equipment is tested as a complete system.

4.2 Photometric Test

• (a) A full photometric test as described in this section is performed before all environmental tests.

  Note: To verify proper colour correction, photometric testing conducted on alternative light source fixtures is done with a detector having an up to date calibration including spectral response data.

• (b) A sampling photometric retest is conducted after the unit has been operated continuously for 1000 hours with normal (12 hour) day/night cycling.
• (c) This sampling consists of measuring the vertical beam pattern for compliance with photometric requirements at a minimum of two of the previously tested horizontal radials.
• (d) Light units are energized by the system power supply and control unit, and are tested for compliance with photometric requirements.
• (e) Incandescent lamps are tested at ±3 percent of their nominal voltage.
• (f) Red light intensity may be measured in white light and then calculated if the glassware manufacturer certifies the chromaticity and transmissivity values of the red filter material for the particular source.
• (g) If more than one lamp type is to be used, the qualification testing is completed for each lamp type.
• (h) For a discharge type flashing system, if the power supply and optical head are separate components, the manufacturer demonstrates that the required photometrics are produced with the units separated by maximum and minimum recommended distances and connected by cable recommended by the manufacturer.
• (i) Photometric test results are in the forms of:
  • (i) points over range of specified angles; and
  • (ii) Horizontal beam pattern: Polar plot (horizontal angle versus candela) with a minimum 30 degree spacing of test points.

4.3 High Temperature Test

• (a) The high temperature test is conducted per MIL- STD-810F, Method 501.4, Procedure II.
• (b) The equipment is subjected to a constant temperature of +55 degrees Celsius for 4 hours after equipment temperature stabilization and be operated throughout the test.

  Note: For steady state temperature testing, consider thermal stabilization to be achieved when the temperatures of critical internal operating components are relatively constant. (Because of test item duty cycling or the operating characteristics, a constant temperature may never be achieved.)

• (c) During the test, the manufacturer demonstrates that the equipment maintains the specified flash rate and (for discharge type flashing light) the proper amount of energy is being delivered to the flashtube as the input voltage is varied by ±10 percent from nominal.
• (d) A visual examination is conducted after the equipment is removed from the chamber. Failure of the equipment to operate as specified is cause for rejection.

4.4 Low Temperature Test

• (a) The low temperature test is conducted per MIL- STD-810F, Method 502.4, Procedure II.
• (b) The equipment is placed in a chamber that maintains a temperature of -55 degrees Celsius for shipping/storage requirements and -40 degrees Celsius for equipment operational requirements.
• (c) Equipment operation is demonstrated at the beginning of the test.
• (d) The equipment storage and shipping low temperature requirement is -55 degrees Celsius.
• (e) The equipment is stabilized and cold soaked at the storage/shipping temperature for one hour.
• (f) The test chamber is then ramped to the -40 degrees Celsius equipment operating temperature at no more than 14.4 degrees Celsius per minute to prevent thermal shock to the equipment.
• (g) The equipment, with input power off, is then exposed to a 24-hour soaking period at -40 degrees Celsius after which the equipment is turned on for one hour, and operates normally.
• (h) The unit achieves specified flash rate and intensity within 1 minute after being energized.
• (i) For rotating type beacons having HID (high intensity discharge) lamps and intended for continuous operation once installed, the unit achieves specified flash rate and the arc struck as to commence an output within 1 minute after being energized and achieves specified intensity within 5 minutes of being turned on.
• (j) During the one hour of operation, the manufacturer demonstrates that the equipment maintains the specified flash rate and, for capacitor discharge type flashing lights (strobe lighting), the proper amount of energy is being delivered to the flashtube as the input voltage is varied by ±10 percent from nominal.
• (k) At the conclusion of the test, a visual inspection is conducted.
• (l) Failure of the equipment to operate as specified is cause for rejection.

4.5 Rain Test

• (a) The wind-blown rain test is conducted per MIL- STD-810F, Method 506.4, Procedure I, paragraph 4.4.2.
• (b) The rain is at a rate of 132 mm/hour with an exposure time of 30 minutes per side.
• (c) The equipment is operated throughout the test. Failure of the equipment to operate as specified is cause for rejection.

4.6 Wind Test

Evidence is provided, either by testing or by calculation of mechanical force, to demonstrate that installed light units meet the wind requirement in paragraph 3.2(c).

4.7 Humidity Test

• (a) The test is per MIL- STD-810F, Method 507.4, paragraph 4.5.2. The equipment is subjected to two complete cycles per Table 507.4-1, except the maximum chamber temperature is +55 degrees Celsius.
• (b) Failure of the equipment to operate as specified is cause for rejection.

4.8 Salt Fog Test

• (a) The salt fog test is conducted per MIL- STD-810F, Method 509.4, paragraph 4.5.2.
• (b) Failure of the equipment to operate as specified is cause for rejection.
• (c) If corrosion is present, the third party certification body determines if it has impacted equipment structural integrity or functionality.

4.9 Sunshine Test

Note: The manufacturer may submit a certificate of compliance (for consideration by the third party certification body) from the manufacturer attesting to UV resistance (per MIL- STD-810F) in lieu of the testing requirements below.

• (a) The equipment is in its normal operational configuration for this test.
• (b) A sunshine test is conducted per MIL- STD-810F, Method 505.4, paragraph 4.4.3, Procedure II for all obstruction lighting equipment with nonmetallic exterior parts or plastic/thermoplastic light covers.
• (c) The equipment is subjected to a minimum of 56 cycles.
• (d) An operational test of the equipment is performed after 56 cycles.
• (e) Any evidence of deterioration of plastic parts: chalking, bleaching, cracking, hazing, or colour changes (yellowing) to the thermoplastic lenses of the test unit is cause for rejection.
• (f) For plastic/thermoplastic optical lenses or covers, the photometric performance is measured after this test.

4.10 System Operational Test

• (a) A system operational test is performed after the unit has been operated continuously without failure for 1000 hours with normal (12 hour) day/night cycling.
• (b) System components are connected with the necessary wiring to electrically simulate an actual installation in which the top and bottom light units on a structure are separated by 600 m for a system composed of CL-856 and/or CL-865 and 150 m for a system composed of CL-857 or CL 866, and the controller separated an additional 760 m.
• (c) Simulated interconnecting cables with equivalent impedance may be used in lieu of full cable lengths.
• (d) The system is energized and operated to demonstrate compliance with all specification operating requirements such as flash rate, flash sequence, photoelectric switching of intensity steps, operation of interlocked devices, and satisfactory operation under input voltage variations.
• (e) If the power supply and optical head are separate components, it is demonstrated that with the maximum and minimum nameplate rated separation between components, proper energy is delivered to the light unit to produce the specified photometrics.
• (f) It is demonstrated that CL-810 and CL-864 lights produce the specified photometric requirement when energized over conductors (actual or simulated) representing the maximum and minimum nameplate rated cable length at the minimum input voltage.
• (g) The monitoring capability of flashing light system controller to 3.3.5.1.1 and 3.3.5.2.2 is verified.
  (effective 2016/03/01)

Appendix C - Aeronautical Assessment Form for Obstruction Marking and Lighting

Form 26-0427E