Pursuant to subsection 5.9(2) of the Aeronautics Act, and after taking into account that the exemption is in the public interest and is not likely to adversely affect aviation safety, I hereby exempt Air Operators using a holdover time determination system (HOTDS) to generate a holdover time determination report (HOTDR) within their approved "Ground Icing Operations Program" from the requirements in sections 1.0, 3.0, 6.0, 6.2, 6.3 and 126.96.36.199 of standard 622.11 "Ground Icing Operations" specifically related to the element of Holdover Timetables (HOT) forming part of the "Ground Icing Operations Program" made pursuant to subsection 602.11(4) of the Canadian Aviation Regulations (CARs), subject to the conditions set out below.
The above-noted provisions are set out in Appendix A of this exemption.
Appendices B and C contain definitions and minimum assurance requirements and performance specifications for holdover time determination systems respectively.
The purpose of this exemption is to authorize air operators to utilize HOTDRs generated by a HOTDS, in addition to or in lieu of their current HOT procedures, as part of their approved "Ground Icing Operations Program".
This exemption applies to an air operator when using a HOTDR generated from a HOTDS as part of its approved "Ground Icing Operations Program", at airports identified in its program.
This exemption ceases to apply to an air operator breaching a condition of the exemption.
This exemption is subject to the following conditions:
- When not utilizing the HOTDS, all requirements/elements of standard 622.11 Ground Icing Operations, must continue to apply as part of the approved Ground Icing Operations Program.
- When utilizing the HOTDS, every requirement/element of standard 622.11 Ground Icing Operations - not explicitly exempted by this exemption must continue to apply as part of the approved Ground Icing Operations Program.
- Prior to using the HOTDS, the air operator shall ensure that the HOTDS meets the applicable minimum performance specification set out in Appendix C of this exemption.
- The air operator shall revise the Company Operations Manual (COM) to include operational procedures associated with the use of the HOTDS. The revised COM must be approved by Transport Canada Civil Aviation prior to the utilization of the HOTDR.
- The air operator shall have a contingency plan in the COM to address the possible outage of the HOTDS.
- The air operator shall develop and provide a training program for their flight crew members and operations personnel on the use of the applicable HOTDS and associated reports.
- When using a HOTDS (during active snow, snow pellets, snow grains, freezing fog, ice crystals, rain on cold soaked wing, freezing drizzle or freezing rain precipitation conditions) that outputs a single value Hold Over Time, the single value Hold Over Time must be considered limiting. Under these conditions, take-off after the single value Holdover Time is exceeded must be prohibited unless an external tactile inspection is conducted and the aircraft is deemed acceptable for flight or the aircraft is re-deiced/anti-iced as required.
- If the weather changes subsequent to receiving an HOTDR, an updated HOTDR must be requested. When more than one HOTDR is received after de/anti-icing, the HOTDR that applies depends on the measurement system used by the HOTDS (see measurement system definitions in Appendix B):
- discrete measurement system: the most limiting HOTDR received must be used.
- continuously integrated measurement system: the most recent HOTDR must be used.
- Except where superseded in this exemption, all notes, cautions, conditions, lists of qualified fluids and application procedures contained in the Holdover Time Guidelines, published by Transport Canada, on an annual basis must continue to apply (for example, respecting the de/anti-icing fluid Lowest Operational Use Temperature (LOUT)).
- The air operator shall identify in the COM the airports where it intends on using a HOTDS for HOT decision-making information.
This exemption is in effect until the earliest of the following:
- March 1st, 2022 at 23:59 EST; or
- the date on which this exemption is cancelled in writing by the Minister of Transport where he is of the opinion that it is no longer in the public interest or that it is likely to adversely affect aviation safety.
The exemption from subsection 602.11(4) of the Canadian Aviation Regulations and sections 1.0, 3.0, 6.0, 6.2, 6.3 and 188.8.131.52 of Standard 622.11 "Ground Icing Operations", issued on February 28, 2014, at Ottawa, Ontario, Canada, by the Director General on behalf of the Minister of Transport is hereby cancelled because it is the opinion of the Minister that it is no longer in the public interest or is likely to adversely affect aviation safety.
DATED at Ottawa, Ontario this 23rd day of February, 2017, on behalf of the Minister of Transport.
"Original signed by"
Director General, Aviation Safety Regulatory Framework
Canadian Aviation Regulations
(4) Where conditions are such that frost, ice or snow may reasonably be expected to adhere to the aircraft, no person shall conduct or attempt to conduct a take-off in an aircraft unless
- (a) for aircraft that are not operated under Subpart 5 of Part VII,
- (i) the aircraft has been inspected immediately prior to take-off to determine whether any frost, ice or snow is adhering to any of its critical surfaces, or
- (ii) the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program; and
- (b) for aircraft that are operated under Subpart 5 of Part VII, the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program.
Standard 622.11 Ground Icing Operations
In order to operate an aircraft under icing conditions in accordance with the requirements of CAR Section 602.11, an operator must have a program as specified in these standards and the dispatch and take-off of the aircraft shall comply with that program. These Ground Icing Operations Standards specify the program elements, for both operations and training that shall be addressed in an operator's Ground Icing Operations Program and described in the appropriate operator's manuals. As applied to Canadian operators, these Standards outline a Program's minimum requirements, which may be adapted according to the needs of the individual operator. Foreign operators should use this Standard as a guideline for the development of their Ground Icing Operations Program in Canada. (…)
3.0 Program Elements
The following elements, which are described in the sections below, will be included in an operator's Ground Icing Operations Program and described in the appropriate manual(s):
- The Operator's Management Plan;
- Aircraft De-icing/Anti-icing Procedures;
- Holdover Timetables;
- Aircraft Inspection and Reporting Procedures; and
- Training and Testing. (…)
6.0 Holdover Timetables
The use of holdover timetables is not mandatory. Holdover timetables, as approved by the Director, Air Carrier, may be used either as guidelines or decision-making criteria in assessing whether it is safe to take off. When holdover timetables are used as decision-making criteria, only high confidence level times shall be used and the procedures to be followed after holdover time has expired must be clearly documented. Where applicable in a Program, an operator's manual will cover the following areas with regard to holdover timetables: (…)
6.2 Use of Holdover Timetables
Holdover timetables provide an estimate of the length of time de-icing/anti-icing fluids are effective. Because holdover time is influenced by a number of factors, established times may be adjusted by the pilot-in-command according to the weather or other conditions. Operators' manuals must describe the procedures to be followed for using holdover timetables. When the tables are used as decision-making criteria, the procedures to be followed by the pilot-in-command (PIC) for varying the established values must also be specified. (…)
6.3 Take-off after Holdover Times have been exceeded
When holdover timetables are used as decision-making criteria, take-off after holdover times have been exceeded can occur only if a pre-take-off contamination inspection is conducted or the aircraft is de-iced/anti-iced again. The operator's Program must specify the procedures to be followed when holdover time is exceeded, and these procedures must appear in the appropriate manuals. (…)
Holdover timetables, approved according to the conditions outlined in section 6 of these Standards, may be used to determine, without a tactile or visual Pre take off Contamination Inspection, that critical surfaces are not contaminated. (…)
Anti-Icing Fluid means a fluid applied to an aircraft as a precautionary procedure that provides protection against the formation of frost or ice and the accumulation of snow on treated surfaces of an aircraft for a period of time;
Deicing Fluid means a fluid applied to an aircraft to remove contamination in the form of frost, ice or snow;
Glycol Pan Measurements means a process to determine precipitation rate by using a glycol-wetted pan that is weighed precisely before and after a timed exposure to precipitation. This methodology has been included in SAE Aerospace Recommended Practice (ARP) 5485 and 5945, and has been historically employed by Transport Canada in the development of fluid holdover time tables for de/anti-icing fluids;
Holdover Time means the determined time that an application of de/anti-icing fluid applied to an aircraft is nominally effective in preventing frost, ice or snow from adhering to the treated surfaces based on using Holdover timetables published by Transport Canada or based on a Holdover Time Determination System Report;
Holdover Time Determination System Report (HOTDR) means a Holdover Time generated by a Holdover Time Determination System.
Holdover Time Determination System (HOTDS) means a near real-time system that samples a number of atmospheric inputs and uses these in conjunction with HOT regression curves and associated coefficients for specific de/anti-icing fluids to produce a holdover time determination report;
Holdover Timetables means tables of holdover times for de/anti-icing fluids published as Holdover Time (HOT) Guidelines, by Transport Canada;
LOUT means Lowest Operational Use Temperature
Manufacturer means the producer of a Holdover Time Determination System;
Measurement System means the way the HOTDS incorporates weather data measurements into an HOTDR.
- discrete measurement system: provides an HOTDR based on weather data measurements taken during a time period (set by the manufacturer) prior to the HOTDR request.
- continuously integrated measurement system: provides an HOTDR based on weather data measurements taken from the time of fluid application to the time of:
- the HOTDR request by the crew; or
- direct push of updated HOTDR information.
Regression Analysis means a data analysis protocol used by Transport Canada to analyze fluid endurance time data for the generation of holdover times for de/anti-icing fluids;
Service Provider, in this context, means a person or organization that:
- provides holdover time reports using a Holdover Time Determination System that meets the application of this exemption; or
- provides precipitation rate, type and temperature information for use by a Holdover Time Determination System in computing Holdover Time Determination System reports that meet the application of this exemption.
Minimum Assurance Requirements and Performance Specifications for Holdover Time Determination Systems
Sections 1, 2 and 3 of this appendix specify the minimum assurance requirements and sections 4 and 5 the minimum performance specifications for the Holdover Time Determination Systems.
1. Quality Management System
1.1 The Air Operator shall ensure that the service provider or manufacturer, establish, document, implement and maintain a quality management system that comprises procedures, processes and resources necessary to provide for the quality management of the Holdover Time Determination System and reports to be supplied.
1.2 The quality management system required by Subsection 1.1 shall at a minimum:
- establish and maintain operational manuals and documentation;
- establish and maintain system commissioning protocols;
- establish and maintain system inspection requirements and methods;
- establish quality control and quality monitoring to include software integrity and data dissemination;
- specify qualifications and training requirements for personnel who commission, inspect or maintain the system, and
- if non-conformance is identified, ensure that action is initiated to determine and correct the cause.
1.3 The documentation in Subsection 1.2 shall be made available to the Minister, upon reasonable notice by the Minister.
2. Training and Qualifications
2.1 The Air Operator shall ensure and document that the manufacturer or service provider maintains records to demonstrate that all persons providing installation, commissioning, inspection and maintenance services of a Holdover Time Determination System are qualified persons who have received appropriate training and have demonstrated sufficient knowledge, skills and competence to perform their assigned duties.
Note: The Air Operator shall ensure and document that the manufacturer or service provider has specified the minimum training requirements applicable to persons engaged in these duties.
2.2 The Air Operator shall make a copy of the documentation referenced in 2.1 available to the Minister, upon reasonable notice by the Minister.
3. Installation, Siting, Operation & Maintenance of Deicing and Anti-Icing Fluid Holdover Time Determination Systems
3.1 The Air Operator shall ensure that the service provider or manufacturer as applicable has established and followed practices, procedures and specifications for the siting, installation, commissioning, operation and maintenance of the Holdover Time Determination Systems, including the co-ordination of activities with the aerodrome operator.
Note: Specifications concerning the siting and installation of equipment on aerodromes are contained in TP 312, Aerodrome Standards and Recommended Practices.
3.2 The input instruments shall be sited in sufficient proximity of each other to provide coherent sampling of meteorological inputs for holdover time determination in transitional weather conditions.
3.3 The Air Operator shall document the requirements of Subsection 3.1 and make a copy available to the Minister, upon reasonable notice by the Minister.
4. Accuracy of Holdover Time Input Instruments and Determination Systems
4.1 The Air Operator shall verify that the manufacturer obtains test data and establish practices and procedures that demonstrate that the data inputs and Holdover Time Determinations meet the accuracy requirements established for each element.
4.2 The Air Operator shall make the documentation required by Subsection 4.1 available to the Minister, upon reasonable notice by the Minister.
4.3 The Air Operator shall verify that the manufacturer has test data that demonstrates compliance of the data inputs and Holdover Time Determinations with Subsection 4.1 in accordance with the following requirements:
- The test data shall be sufficiently complete to assure that the results are representative of the design and performance specifications of the system and include the following:
- For those instruments for which it is practical, the relationship between the value indicated by an instrument and the corresponding known value of a measure and;
- The testing of instruments over a range that is representative of the expected environmental conditions (regardless of whether in a controlled environment or in the field); and
- Testing of instruments in comparison with other instruments or human observations, in the outdoor operational environment, where practical.
- The test data shall consist of the following:
- Raw data collected during testing, and
- The results of the reduction and analysis of the data.
- The Air Operator shall verify that the person verifying the test data in accordance with paragraph (d) confirms that the results of the reduction and analysis of the test data demonstrate that the data inputs and Holdover Time Determinations meet the accuracy requirements set out in this Appendix under operational conditions encountered by the Holdover Time Determination System;
- The Air Operator shall confirm that the manufacturer's test data have been verified as meeting the accuracy requirements of this Appendix by a person who is:
- Independent from the manufacturer of the Holdover Time Determination System and from the service provider and has a degree in the natural or applied sciences of mathematics from a recognized university and experience in: instrumental references, standards and traceability, methods of statistical analysis and an understanding of the operating principles and use of the instruments involved; or
- A licensed professional engineer (P.Eng.) in Canada.
- The Air Operator shall verify that the manufacturer obtains a written confirmation of the verification of the test data from the person who verified the test data pursuant to paragraph (d) and shall, upon reasonable notice by the Minister, provide a copy to the Minister;
- The Air Operator shall ensure that the manufacturer demonstrates and confirms that the HOTDS has built-in fault detection checks that, in the event of system input/output failure (such as loss of an input instrument or corruption of data in a HOTDR) or other critical system hardware or software failure, prevent a misleading report from being issued. Demonstration shall be carried out on an end-to-end basis from input instruments in the field to delivery of Holdover Time Determination System Reports to the Air Operator.
- The Air Operator shall ensure that the manufacturer demonstrates initial and ensures ongoing quality assurance of the computational software, hardware and end to end data integrity as follows:
- The software must be designed, developed, produced and maintained in accordance with appropriate software assurance standards.
- The hardware must be designed, developed, produced and maintained in accordance with appropriate hardware assurance standards.
- End-to-end data integrity shall include means of minimizing misleading data caused by all sources (ex: corrupted fluid coefficients, corrupted data transmissions, etc.) through the use of CRC checks or similar safeguards.
- The Air Operator shall ensure that the manufacturer confirms that the accuracy of the timing methods or device used to establish the time of the report is sufficient for the intended purpose; and
- The Air Operator shall ensure that the manufacturer documents the processes and procedures used to comply with the requirements of paragraphs (a) and (h) and shall make them available to the Minister, upon reasonable notice by the Minister.
5. Technical Requirements for Data Inputs and Holdover Time Determinations
5.1 The Air Operator shall ensure that the manufacturer establishes and document practices and procedures for compliance with the provisions of Subsections 5.1.1 thru 5.1.23, which are applicable to the manufacturer's Holdover Time Determination System, and make a copy available to the Minister, upon reasonable notice by the Minister.
5.1.1 If required by the HOTDS, surface wind data inputs shall meet the following requirements:
- Wind instruments shall be ice resistant by design;
- The instruments shall be sited so as to provide representative input to any compensation factors that are generated to correct precipitation accumulation rates during high wind conditions; and
- The instruments shall function for winds of at least 100 knots.
5.1.2 The accuracy of wind sensors and outputs shall be such that;
- The direction, if utilized, is correctly measured within ± 10 degrees; and
- The mean speed is correctly measured within ± 2 knots up to 20 knots and with 10% above 20 knots.
5.1.3 The accuracy of the wind instruments shall be established in accordance with Subsection 5.1.2, paragraphs (a) and (b), to at least a 95% confidence in wind tunnel testing.
5.1.4 Systems used for the determination of precipitation shall:
- Meet or exceed accuracy requirements as follows with reference to human observations:
- Correctly detect the presence of precipitation of a water equivalent rate of at least 2.0 g/dm2/h, other than drizzle, at least 90% of the time;
- Correctly detect the presence of and distinguish between liquid or frozen precipitation, of a water equivalent rate of at least 2.0 g/dm2/h, at least 80% of the time; and
- Correctly detect the presence of ice accretion or freezing precipitation, of at least 2.0 g/dm2/h, with at least a 90% probability.
- Differentiate between and, where applicable determine the intensity of: rain, freezing rain/freezing drizzle, and snow;
- Accurately detect the presence of fog, or freezing fog conditions;
- Indicate that type of precipitation is "unknown", if the type cannot be determined; and
- In the event of unknown precipitation, the equipment shall report that a holdover time is unavailable.
5.1.5 Temperature measurements shall be accurate to within 1°C.
5.1.6 The accuracy requirements of Subsection 5.1.5 shall be demonstrated with at least a 95% confidence level during laboratory testing that is traceable to a reference standard.
5.1.7 Precipitation rate measurements shall be analyzed in reference to simultaneously recorded glycol pan measurements for all precipitation types, excluding freezing fog.
5.1.8 The Holdover Time Determination System precipitation rate measurements shall conform to the glycol pan measurements (ref.: SAE ARP 5485), within the following tolerances:
- From 0 to 10 g/dm2/h: +/- 3.0 g/dm2/h
- Above 10 g/dm2/h to 25 g/dm2/h: +/- 6.0 g/dm2/h
- Above 25 g/dm2/h: +/- 14.0 g/dm2/h
5.1.9 The accuracy requirements of Subsection 5.1.8 shall be demonstrated with at least a 95% confidence level during comparative tests with the HOTDS and glycol pans.
5.1.10 The precipitation rate input for the purpose of computing fluid holdover time (Subsections 5.1.12 to 5.1.18) shall be:
- the precipitation rate determined by the HOTDS; plus
- the tolerance (within a 95% confidence level) that has been demonstrated for each precipitation type and range in 5.1.8, specific to that HOTDS.
5.1.11 Notwithstanding section 5.1.10, the precipitation rate input for the purpose of computing fluid holdover time (Subsections 5.1.12 to 5.1.18) shall not be less than 2.0 g/dm2/h.
Holdover Time Determinations
5.1.12 The HOTDS shall incorporate the most current regression curves and associated coefficients. These regression curves and associated coefficients are:
- 184.108.40.206 those obtained from or published by TC, or
- 220.127.116.11 those where traceability and validity has be demonstrated to be equivalent to those in 18.104.22.168.
5.1.13 Holdover Time Determinations from the system for all de/anti-icing fluids shall be computed using the regression curves and associated coefficients referenced in 5.1.12.
5.1.14 Holdover Time Determinations from the system, shall be verified, for each fluid, against known fluid dilution, precipitation type, rate and temperature inputs to ensure that regression curves and associated coefficients have been correctly implemented within the system.
As a minimum this verification will include:
- 22.214.171.124 normal range test cases; and
- 126.96.36.199 test cases outside the normal range to verify robustness.
5.1.15 Holdover Time Determinations for Freezing Drizzle or Freezing Rain conditions shall be based on computing the associated Holdover Time for each one of those precipitation conditions and using the resulting lowest value. The lowest precipitation rate input for this calculation will be 5 g/dm2/h unless a lower Lowest Use Precipitation Rate (LUPR) in Freezing Drizzle or Freezing Rain is published in the documents referenced in 5.1.12.
5.1.16 Holdover Time Determinations shall be inhibited in Freezing Precipitation (Freezing Fog, Freezing Drizzle or Freezing Rain) conditions exceeding 25 g/dm2/h.
5.1.17 Holdover Time Determinations shall be inhibited in Snow conditions exceeding 50 g/dm2/h.
5.1.18 Holdover Time Determinations shall be inhibited in Rain on Cold Soaked Wing conditions exceeding 75 g/dm2/h.
5.1.19 In accordance with the currently accepted practice for HOT table development, Holdover Time Determinations from the system for Type II, III and IV de/anti-icing fluids shall be capped as follows:
- Freezing Fog 4 hrs;
- Snow 2 hrs;
- Freezing Drizzle 2 hrs;
- Light Freezing Rain 2 hrs;
- Rain on Cold Soaked Wing 2 hrs.
5.1.20 Where applicable, the notes, conditions, cautions incorporated into the annually published holdover time guidelines shall be respected in computation outputs by the HOTDS.
5.1.21 0°C must be input into the HOTDS regression calculation when measured temperature is above 0°C.
Holdover Time Determination Reports
5.1.22 A Holdover Time Determination Report shall contain as a minimum de/anti icing Holdover Time(s) and fluid type. The report may contain additional items such as:
- Precipitation type;
- Precipitation intensity;
- Precipitation trend; and
- Fluid brand
These additional items shall be as agreed to with the service provider and/or the aircraft operator.
5.1.23 The service provider shall retain a copy of each Holdover Time Determination Report for at least 24 months.
5.1.24 The service provider shall provide a copy of the Holdover Time Determination Reports required by 5.1.22 to the Minister, upon reasonable notice by the Minister.
- Date modified: