A93Q0245 - Collision with Terrain - Fonds du Service Aérien Gouvernemental Shorts SD3-30 Variant 300 C-FPQE - Umiujaq, Quebec - 01 December 1993
Synopsis
The crew was on a flight from Kuujjuarapik to Umiujaq, Quebec. During the turn onto the final approach to Umiujaq Airport runway 21, the aircraft stalled. The pilot-in-command regained control of the aircraft but he was unable to pull up sufficiently to clear the obstacles, and the aircraft crashed. The two pilots and two of the 11 passengers sustained minor injuries.
The Board determined that the stalling speed of the aircraft increased due to ice on the leading edge of the wings and because the pilot made a steep turn; the aircraft stalled at an altitude from which the pilot was unable to recover. A contributing factor was the crew's decision to continue the visual approach into Umiujaq despite the weather conditions reported.
FOOTNOTE
(10) J.L. Harris, Sr., "Avoid", The Unanalyzed Partner of "See". ISASI Forum #2, 1983 p.16
Safety Action Required
(as presented in the TSB Report)
Obstacle Clearance Altitudes
During this investigation, it became evident that Article 553 of the Air Regulations was being interpreted in a way such that its application with respect to operations in uncontrolled airspace was questionable. The regulation, when used as a reference for the flight conditions required for the transition from IFR flight to VFR flight in uncontrolled airspace, appears to have been ambiguous to such an extent that the Transport Canada (TC) Quebec regional office had an interpretation substantially different from that of TC's head office in Ottawa.
The flight procedure that brings into question the intent of the regulation is an en route IFR descent in instrument meteorological conditions (IMC) to conduct a VFR landing. Air Regulation 553 requires that aircraft in IFR flight be flown at an altitude 1,000 feet above the highest obstacle within 5 miles of the estimated position of the aircraft, except when taking off or landing (3). The descent procedure used by the aircrew in this occurrence, and interpreted by the TC regional office as being acceptable, could eliminate this safety margin. Using a line of thinking consistent with this interpretation, a crew could descend an aircraft in IMC, without being on an approved instrument approach, to an altitude where visual meteorological conditions (VMC) were anticipated, as long as the descent was considered to be for the purpose of landing. The Board and TC's head office both believe that this was not the intent of the regulation.
The new Canadian Aviation Regulations (CARs)(recently announced in the Canada Gazette) contain a detailed section on minimum altitudes to ensure obstacle clearance in IFR flight; however, the CARs are no clearer than the Air Regulations as to what differentiates the en route and/or approach phase of a flight from the landing phase. Nevertheless, until the CARs are in effect, aircrew are still required to fly in accordance with the existing Article 553; therefore, some aircrew may still believe that a descent is permissible to any altitude while attempting to transition to a VFR landing. Moreover, given the increasingly widespread use of GPS for navigating in remote areas and considering GPS' reputation for accuracy, aircrew may be more likely than ever to question the need for the 1,000-foot safety buffer.
The Board is concerned that regulatory officials and the operator of a fleet of state aircraft apparently did not question the appropriateness of a procedure that put aircraft, crew, and passengers at an increased level of risk. Therefore, the Board recommends that:
The Department of Transport advise the aviation community, including Transport Canada regional staff, of the correct interpretation of Air Regulation Article 553;(A96-01)
and
The Department of Transport clarify the wording of the CARs with respect to descents for landing in uncontrolled airspace to ensure that the intended level of safety is not jeopardized through misinterpretation. (A96-02)
Transport Canada's Response:
Transport Canada agrees that, in general, further efforts are required to eliminate confusion that may exist related to IFR flight in uncontrolled airspace. However, further clarification of Air Regulation (AR) 553 (which requires that aircraft maintain certain altitudes and distances from obstacles while operating under IFR) is unwarranted if related regulations and guidance material are considered.
Regulations cannot be considered in isolation of other relevant regulations or guidance material; to do so may lead to misinterpretation. When other regulations and guidance material are considered, the intent of AR 553 becomes clear. For instance, paragraph 548(1) (c) is relevant in this case, and applies to the pilot-in-command of an aircraft that is in IFR flight of IFR weather conditions-..."where the aircraft makes an approach to an airdrome or a runway, ensure that the approach is made in accordance with the instrument approach procedure, unless otherwise authorized by the appropriate air traffic control unit." At the time of the accident there was no published instrument approach procedure for Umiujaq, Quebec.
Guidance material is contained in AIP Canada in Section 9.0 - Instrument Flight Rules - Arrival Procedures, paragraph 9.7.1 "In accordance with Air Reg. s.553, the aircraft shall be flown at an altitude of at least 1,000 feet above the highest obstacle located within a horizontal radius of 5 miles from the estimated position of the aircraft in flight until the required visual reference is acquired in order to conduct a normal landing. Pilots are cautioned that conducting a contact approach in minimum visibility conditions introduces hazards to flight not experienced when flying IFR procedures." When considered together, the relevant regulations and guidance material provide clear intent.
Notwithstanding the above, confusion may exist as to the application of IFR in uncontrolled airspace. The department has taken steps to eliminate this possibility in the following ways:
- Different interpretations have existed regarding the application of the Instrument Flight Rules. Some were of the opinion that IFR did not apply in uncontrolled airspace, while others were of the opinion that IFR did not apply unless the aircraft was being operated in accordance with an IFR air traffic control clearance. In order to minimize the possible misinterpretation of application, CARs Part VI, Division VII - Instrument Flight Rules, section 602.121, General Requirements, has been drafted in such a way as to eliminate any question regarding the application of the division.
- The CARs Training Course that was delivered at least three times in every region over the winter contained, in its course material, information on the new construction of the division pertaining to instrument flight rules. The training was given not only to familiarize Transport Canada staff and the aviation community with the new regulations, but also to begin to establish uniform interpretation of the content and application of the regulations.
It is believed that these actions will meet the intent of recommendations A96-01 and A96-02; namely, to eliminate any confusion regarding the application of regulations in uncontrolled airspace. The Department will monitor compliance with the CARs, paying particular attention to possible misinterpretation of intent on the part of both departmental staff and the aviation community.
FOOTNOTE
(3) The Air Regulations define "landing" as the act of coming into contact with a supporting surface; this includes the immediately preceding and following acts.
Safety Action Required
(as presented in the TSB Report)
State-Owned Aircraft
In Canada, several departments and agencies of the federal and provincial governments operate fleets of aircraft. These fleets vary in size from just a few aircraft to over 100 aircraft, often with a mixture of aircraft types in any one fleet. The aircraft are frequently used to transport passengers, albeit not in a commercial capacity. The state aircraft generally operate under Air Navigation Order (ANO) I, No. 2, which regulates the transport of passengers in private aircraft. Private aircraft in this context include state and corporate aircraft. Thus, a private aircraft with a passenger-carrying capacity of only a few passengers and state/corporate aircraft with significant passenger-carrying capacity (often significantly greater than that of the accident aircraft type) are treated in a similar manner from a regulatory perspective. The Fonds du Service Aérien Gouvernemental is classified as a state-owned operation and was operating under ANO I, No. 2.
Commercial operations are generally conducted in accordance with ANO VII, No. 2 (large aircraft), and ANO VII, No. 3 (small aircraft). The aircraft type involved in this accident would be operated under ANO VII, No. 2, in a commercial operation. There are significant differences between ANO I, No. 2, operations and ANO VII (particularly ANO VII, No. 2) operations in the areas of the requirement for an operating certificate, operational requirements, crew training and qualifications, and regulatory overview.
In the late 1980s, the predecessor to the TSB, the Canadian Aviation Safety Board (CASB), became concerned about the number of occurrences involving another operator of a large fleet of state aircraft, the RCMP. It was noted at that time that a number of the practices and procedures meant to enhance safety in the commercial aviation sector were absent in the day-to-day operation of that fleet. The CASB suggested that the operator request an independent safety survey to assist in identifying shortcomings in the operation. A safety survey was subsequently done by TC and corrective measures were taken. Some of these measures were in excess of ANO I, No. 2, requirements and more in line with ANO VII requirements. The number of significant occurrences involving RCMP aircraft has reduced considerably since 1990.
Following this accident, and with the concurrence of Service Aérien, Transport Canada initiated a post-accident safety survey of the organization. As a result of this survey, changes were made to the organization's managerial staff. The TSB was unable to determine what other changes, if any, resulted from this survey.
In providing its regulatory overview of commercial operators, Transport Canada uses risk management indicators to identify those carriers possibly requiring extra surveillance and audit. However, operators of state aircraft do not come under the same regulatory scrutiny; thus, indicators of increasing risk are less likely to be detected. The operation of TC's own fleet of aircraft is voluntarily subjected to the requirements of an operating certificate similar to that of commercial carriers.
The recently announced CARs will require state and private operators of large or turbine-powered, pressurized passenger aircraft to adhere to more demanding safety standards. However, these standards are still not equivalent to those applicable to commercial air carriers. It is recognized that the operations in which state aircraft are often engaged are unique, and that, for the most part, they do not involve the travelling public. Yet, when passengers are regularly carried on state aircraft, it is reasonable for these passengers to expect that the aircraft and aircrew involved in state operations are subject to the same regulatory requirements as commercial carriers. The Board believes, therefore, that state operations would benefit from the increased standards and regulatory overview applicable to commercial operations. Therefore, the Board recommends that:
The Department of Transport require that the operators of state aircraft be subject to regulatory overview, as practicable, equivalent to that of similar commercial operations. (A96-03)
Transport Canada's Response:
The Private Aeroplanes Passenger Transportation Order, Air Navigation Order Series 1, Number 2 was introduced in March of 1982 to address findings following several corporate aviation accidents involving turbine powered, pressurized aeroplanes, that showed evidence of a lack of crew training, standardization, and, coordination. Since the introduction of this order there have been no passenger fatalities and very few accidents with this group of operators.
The Quebec Government Air Service is one of the larger fleet operators regulated by ANO Series 1, No 2 (CAR 604) and operates a range of aircraft including small aircraft, fire suppression aircraft and several large passenger carrying aeroplanes. While the operation of Convair CV580 aircraft in an employee transportation role appears to be quite active, this operation is not a publicity available air service and as such does not warrant the imposition of increased commercial standards.
At the time of the subject accident, there were shortcomings in the flight operations of the Quebec Government Air Service. Following this accident, Transport Canada Aviation conducted a confidential safety audit for the Quebec Government and subsequently worked with the Quebec Government Air Service to address deficiencies. Since that audit, there have been no accidents, occurrences, or risk indicators to merit an increased level of surveillance and audit.
The implementation of CAR 604 - Private Operator Passenger Transportation will introduce new safety requirements in areas such as, flight attendant training, passenger briefing, flight duty time limitations and flight crew training. As new regulations which will further enhance the safety of these operations are to be introduced, and after consideration of the discussion presented in TSB Report number A93Q0245, Transport Canada does not consider the imposition of commercial air operator regulations and standards on state operators to be necessary.
A95H0008 - Mid-Air Collision Between - Bearskin Airlines Fairchild Metro 23 C-GYYB and Air Sandy Inc. Registration PA-31 Navajo C-GYPZ - Sioux Lookout, Ontario 12 nm NW - 01 May 1995
Synopsis
Air Sandy flight 3101, a Piper PA-31 Navajo with one pilot and four passengers on board, had departed Sioux Lookout on a flight to Red Lake, Ontario. Bearskin Airlines flight 362, a Fairchild Swearingen Metro 23 with a crew of two and one passenger on board, was inbound to Sioux Lookout on a flight from Red Lake. The two aircraft collided at 4,500 feet above sea level, approximately 12 nautical miles northwest of Sioux Lookout. All eight occupants were fatally injured.
The Board determined that neither flight crew saw the other aircraft in time to avoid the collision. Contributing to the occurrence were the inherent limitations of the see-and-avoid concept which preclude the effective separation of aircraft with high closure rates, the fact that neither crew was directly alerted to the presence of the other aircraft by the Flight Service specialist or by onboard electronic equipment, and an apparent lack of pilot understanding of how to optimize avoidance manoeuvring.
Safety Action Taken
(as presented in the TSB Report)
Operator Action
Subsequent to the accident, Bearskin Airlines developed procedures to reduce the risk of mid-air collisions in the busy Sioux Lookout area. These procedures include a requirement that all Bearskin aircraft be flown at a speed of less than 150 knots when operating within 5 nm of the Sioux Lookout airport. This reduction in airspeed should decrease the probability of mid-air collision by increasing both the likelihood of detecting conflicting traffic and the time available to take evasive action once conflicting traffic has been detected.
Transport Canada Action
Transport Canada has taken action to increase pilot awareness of procedures to reduce the likelihood of mid-air collisions. An Aviation Notice entitled "Mid-Air Collision Alert Bulletin" was issued in July 1995. The notice informs pilots of the increased potential for collision when using GPS and stresses the benefits of using arrival, departure, and position reports in order to be alerted to potential conflicting traffic. The notice also included an enhanced version of the Mid-Air Collision Avoidance Guidelines.
Two posters have been produced: the first, entitled "MF/ATF Communications Requirements," reviews applicable pilot reporting/communication requirements; the second, entitled "GPS-Traffic Separation," suggests flying one or two miles right of the centre line of the track when navigating with GPS in order to avoid conflict with opposite direction traffic.
In addition, Transport Canada has published four articles about collision avoidance in issue 2/96 of the Aviation Safety Newsletter.
Furthermore, Transport Canada (Central Region) has established a Mandatory Frequency Working Group. In July 1995, the group solicited input from the aviation community concerning the adequacy of procedures associated with mandatory frequency areas. Various procedural and structural solutions to problems related to MF areas are being evaluated in light of the responses received.
MF Area Procedures
The new Canadian Aviation Regulations, which are expected to come into force in 1996, change the reporting procedures for aircraft approaching an MF area. The pilot-in-command of a VFR aircraft will now be required, where circumstances permit, to call at least five minutes before entering the MF area. This change will give both arriving and departing aircraft more warning of conflicting traffic, and will effectively expand the radius of the MF area in accordance with an aircraft's speed; under these procedures, given the radius of the MF area and the ground speed of the Metro, the Bearskin flight would have been required to contact Sioux Lookout FSS at least 25 nm back from the airport.
FSS Traffic Awareness
Flight Service specialists are required to provide airport advisory information to aircraft operating to or from locations within an MF area. A summary of known pertinent aircraft traffic that may affect the aircraft's safety must be provided, and must be updated if the specialist becomes aware of potential conflicts. Pilots use traffic advisories to assist in seeing and avoiding conflicting traffic. The resources available to specialists to provide these advisories, however, are scant.
The quality of traffic advisories can be adversely affected by inaccurate aircraft position reports, communication errors, and frequency congestion. Further inaccuracies can be introduced when specialists rely primarily on radio to determine the position and intentions of aircraft in their area, then attempt to recognize potential conflicts by extrapolating from their mental picture of the current traffic situation. As traffic densities and aircraft speeds increase, a specialist's ability to integrate available information and provide credible and timely traffic advisories is adversely affected, thereby increasing the risk of collision.
The Board understands that relatively low cost equipment is now available which can provide a pictorial display of aircraft traffic. If used by specialists, such systems could reduce the potential for cognitive errors, reduce frequency congestion, and facilitate remote monitoring. In light of the reduced risk of collision which might accrue through the use of such systems, the TSB forwarded a Safety Advisory to Transport Canada (TC) suggesting that TC evaluate the use of systems which provide pictorial displays of aircraft position (such as ground-based TCAS systems and Personal Computer systems displaying radar data via land line) to assist Flight Service specialists in identifying potential conflicts and in providing accurate and timely traffic advisories.
Although the specialist at Sioux Lookout advised two aircraft on the MF of the approaching Bearskin 362 flight while Air Sandy 3101 was on the same frequency, it is not known if the Air Sandy pilot heard the traffic advisory concerning the Bearskin flight. The TSB is not aware of the extent to which specialists are ensuring that aircraft are aware of conflicting traffic and has suggested in a Safety Advisory that Transport Canada consider placing increased emphasis in this area during quality assurance reviews.
Safety Action Required
(as presented in the TSB Report)
Separation Procedures for Aircraft Navigating with GPS
GPS has been approved for use under VFR and as a backup aid to navigation under IFR; approval as a primary IFR navigation aid is imminent. The Canadian Air Navigation System is rapidly moving toward increased reliance on this inexpensive and accurate navigation system.
In 1995, the Board made two recommendations to TC aimed at reducing the potential for GPS-related occurrences resulting from the use of unapproved equipment, inadequate understanding of the system, or lack of approved approaches. Transport Canada agreed with the recommendations and outlined several initiatives to expedite the implementation of GPS standards and raise the aviation community's awareness of the limitations and safe use of GPS.
The correct use of GPS decreases the average displacement of an aircraft from the centre line of its desired track; consequently, if separation procedures fail, the probability of a mid-air collision will increase (see LP 95/95). This increased risk of collision applies to both IFR and VFR aircraft in all types of operations.
The probability of collision for aircraft using GPS could be reduced if pilots used the area navigation (RNAV) capabilities of GPS to avoid high traffic routes, either by flying at an off-set distance from the centre line of these routes or by creating their own routes. Although TC has taken some action in this regard (see Transport Canada Action), the action is limited in scope and short term in nature. Given the increasing use of GPS, and the increased potential for mid-air collision associated with its use, the TSB recommends that:
The Department of Transport expedite the development and implementation of safe separation procedures for the use of GPS in navigation. (A96-04)
Transport Canada's Response:
Transport Canada (TC) is very active on all GPS-related issues, including its safe usage in navigation; however, TC considers that the introduction of GPS does not require any change to current rules and procedures regarding aircraft separation. In VFR operations, there is no rule that requires pilots to follow specific tracks. Some pilots follow airways or air routes anchored by traditional ground aids while VFR, but GPS offers the chance to use any point-to-point route. This offers more routes if everyone uses GPS. When departing from an airport, a VFR pilot using GPS will generally take up a direct course to destination at some point after takeoff. This point may be different on each flight, depending on wind, runway in use, traffic, and aircraft performance. This automatically creates an offset. Since all RNAV systems allow aircraft to be flown on essentially random tracks, it is difficult to envision a separation criterion which would be more effective than that already provided for these systems. Once at cruise altitude, even when on the same track, separation is assured by flying at an altitude appropriate to direction of flight.
In IFR operations, air traffic control service ensures separation regardless of the navigation guidance being used. The key to avoiding collisions near airports like Sioux Lookout, where there is a mix of IFR and VFR aircraft, is communications. While arriving and departing, pilots have not reached opposite direction cruise altitudes, so they must be extremely vigilant. GPS makes communications more effective because it provides pilots with more accurate position, speed, and ETA information than is possible with traditional aids. Regardless of the precision of the guidance used by the pilot, it is critical, particularly when in the vicinity of an uncontrolled airport, to communicate position and intentions.
A Satellite Navigation Program Office (SNPO) has been established to work on issues specific to GPS. Current issues of concern and study include the human factors aspects of the GPS avionics, particularly during approach operations, the reliability of the avionics data base and electromagnetic interference. The SNPO regularly updates A.I.P. Canada, writes safety articles, publishes its own newsletter and has recently prepared a notice for the Canada Air Pilot, in each case advising pilots how to use GPS safely.
Transport Canada will continue to address and monitor GPS issues, and will also continue to regularly publish articles in the "Aviation Safety Letter" newsletter to sensitize the aviation community.
Collision Avoidance
Procedures to separate aircraft are not always followed (as evidenced by IFR loss-of-separation incidents) and are not always effective (for example, during VFR climb/descent). There have been eight mid-air collisions in Canada since 1991, and 142 reported occurrences where aircraft safety was compromised due to a loss of separation. Where procedures to separate aircraft fail, pilots may have to rely on the see-and-avoid method to avoid a mid-air collision. This method, however, becomes less effective as aircraft airspeeds increase.
The estimated closing speed of the accident aircraft was 410 knots. At this speed, the probability of the pilots of one aircraft acquiring the other aircraft in time to take effective evasive action was only about 20 per cent (LP 086/95 and LP 001/96 refer). This probability would have been doubled if the closing speed had been reduced to about 300 knots. In light of the increased probability of acquiring conflicting traffic at reduced airspeeds, the TSB recommends that:
The Department of Transport ensure that aircraft are flown at reduced airspeeds, consistent with safe manoeuvring, in the vicinity of aerodromes where separation relies primarily on the see-and-avoid concept. (A96-05)
Transport Canada's Response:
Regulations require that all aircraft operating below 3000 feet above ground level within 10 nautical miles of a controlled aerodrome operate at 200 knots or less unless otherwise authorized by ATC. This requirement is based on the following premises: that the aerodrome has sufficient air traffic to warrant control; that the reduction in speed will enhance visual separation as well as the provision of ATC separation; and that ATC can provide authorization to those aircraft that cannot operate at slower speeds. Making the regulation universally applicable may mean that at those locations without ATC and where ATC authorization could not be obtained, all aircraft unable to reduce to the lower speeds would be in violation of the regulation.
Although in some instances a regulation would be unenforceable, the proposal will be examined further and could become a recommended practice. Good communications with users and their early participation in determining the need for speed will go a long way toward resolving this issue.
The pilots of aircraft operating in visual conditions, regardless of the type of rules under which they may be operating, are responsible for maintaining a satisfactory lookout and avoiding other aircraft and obstacles. At controlled aerodromes, ATC will provide separation between IFR aircraft and conflict resolution between IFR and VFR aircraft. However, no separation is provided between IFR and VFR aircraft and conflict resolution between VFR aircraft is only provided on pilot’s request.
Consideration will be given to amending the information in A.I.P. Canada to include a recommendation that pilots should operate at reduced speeds when in the vicinity of uncontrolled aerodromes.
Even if aircraft are flown at reduced airspeeds, pilots must be able to recognize a collision threat and take appropriate action if a collision is to be avoided. Transport Canada's Flight Instructor's Guide advocates the use of a steep turn to avoid collisions; however, this manoeuvre may actually increase the probability of impact if it is initiated when the aircraft are inside the range of approximately 10 seconds to impact (10) (evidence indicates that the Navajo was steeply banked at the time of the collision).
Since inappropriate responses to a risk of collision situation may increase the risk of a mid-air collision, the TSB recommends that:
The Department of Transport take both long- and short-term action to increase the ability of pilots to recognize in-flight collision geometry and optimize avoidance manoeuvring. (A96-06)
Transport Canada's Response:
Transport Canada will take action to increase the ability of pilots to recognize in-flight collision geometry and optimize avoidance maneuvering. Specifically, the Flight Instructor Guide will be amended and the issue will be addressed in a new Transport Canada publication, "Human Factors in Aviation".
TCAS
The see-and-avoid method of traffic separation can be much more effective if pilots are alerted to the existence and relative location of conflicting traffic. TCAS I provides such proximate traffic alerts (TAs).
Although United States Federal Aviation Regulations would have required the Metro to be TCAS equipped, and many other countries are instituting TCAS requirements, no such requirements exist or are planned in Canada.
In view of the demonstrated capabilities of TCAS, and the increasing risk of collision due to improved navigational accuracy, increasing aircraft speeds, and mixed VFR/IFR traffic at uncontrolled airports such as Sioux Lookout, the Board recommends that:
The Department of Transport conduct an analysis of the benefits of requiring commercial passenger- carrying aircraft to be equipped with TCAS versus the risks associated with operating aircraft without TCAS. (A96-07)
Transport Canada's Response:
The Canadian Aviation Regulation Avdisory Council (CARAC) has formed a Working Group to study what additional equipment may be required in Canada to enhance safety and harmonize with the requirements of the U.S. regulations, in particular, GPWS, TCAS and wind shear alerts. This working group will analyze the benefits of TCAS and make recommendations with respect to future regulatory action. The first meeting of the working group is scheduled for the Fall of 1996.
FOOTNOTE
(10) J.L. Harris, Sr., "Avoid", The Unanalyzed Partner of "See". ISASI Forum #2, 1983 p.16
A95C0026 - Controlled Flight into Terrain - Bearskin Lake Air Services Ltd. - Beechcraft A100 C-GYQT - Big Trout Lake Airport, Ontario - 3 mi NW 21 February 1995
Synopsis
The Bearskin Lake Air Services Ltd. Beechcraft A100 was on a regular scheduled flight, under visual flight rules, to Big Trout Lake Airport, Ontario, with nine passengers and a crew of two on board. The crew were flying the aircraft over a lake about four miles northwest of the airport for a landing on runway 14 when whiteout conditions were encountered. The aircraft descended in controlled flight into the frozen surface of the lake. The crew and several passengers sustained serious injuries. Rescuers from the local community reached the aircraft about two hours after the crash and all eleven survivors were rescued within four hours.
The Board determined that, while the crew were manoeuvring the aircraft to land and attempting to maintain visual flying conditions in reduced visibility, their workload was such that they missed, or unknowingly discounted, critical information provided by the altimeters and vertical speed indicators. Contributing factors were the whiteout conditions and the crew's decision to fly a visual approach at low altitude over an area where visual cues were minimal and visibility was reduced.
FOOTNOTE
(10) J.L. Harris, Sr., "Avoid", The Unanalyzed Partner of "See". ISASI Forum #2, 1983 p.16
Safety Action Taken
(as presented in the TSB Report)
Airport Elevation
Subsequent to this occurrence, the Canada Flight Supplement was amended to indicate the airport elevation of Big Trout Lake as 777 feet asl.
Visibility Requirement in Uncontrolled Airspace
In the proposed Canadian Aviation Regulations (CARs), the visibility requirement for aircraft operating under visual flight rules in uncontrolled airspace below 1,000 feet agl will be increased to two miles from the current one mile requirement. However, there will be provisions for Transport Canada (TC) to allow commercial operators to operate aircraft at lower visibilities provided that certain pilot training and aircraft equipment criteria are met.
Operating Instruction for ELTs
In this occurrence, the passengers had difficulty operating the ELT. A TSB Aviation Safety Advisory was forwarded to Transport Canada regarding the need for the placarding of clear instructions for the use of ELTs, with the suggestion that this requirement be considered in the new regulations.
Ground Proximity Warning System (GPWS)
Canadian regulations require only commercially operated, large turbo-jet powered aircraft (capable of carrying 10 or more passengers and with 15,000 kg or greater maximum certified take-off weight) to have GPWS installed. In the United States, all turbine powered (turbo-jet and turbo-prop) aeroplanes with 10 or more seats, notwithstanding their weight, require an operating GPWS. The aircraft in this occurrence, the Beechcraft A100, is certified for more than 10 seats; however, the Canadian regulation for GPWS is limited to turbo-jet powered aircraft only.
The Board believes that the increased level of safety provided by GPWS should not be related to an aircraft's type of propulsion; rather the requirement for GPWS installation should be based on the role of the aircraft and its passenger-carrying capacity. Therefore, the Board previously recommended that:
The Department of Transport require the installation of GPWS on all turbine-powered IFR- approved commuter and airline aircraft capable of carrying 10 or more passengers. (A95-10, issued 21 March 1995)
Transport Canada replied that it would submit the GPWS issue to the Canadian Aviation Regulation Advisory Council (CARAC). The CARAC is establishing a sub-working group to look into safety systems, such as GPWS, traffic collision avoidance systems, and windshear avoiding systems.
Safety Action Required
(as presented in the TSB Report)
Post-Accident Survivability
As evidenced in this occurrence, accident survival can depend to a large extent on post-crash conditions. Notwithstanding that this operator had complied with all regulations, the first aid kit on board the aircraft was not adequate to deal with the injuries to the passengers, some survivors suffered from hypothermia as a result of insufficient protection from the elements, and the passengers had difficulty following the instructions for post-crash use of the ELT. The issue of post-accident survivability has been an ongoing concern in commercial aviation. In 1986, following a PA-31 accident, the predecessor to the TSB, the Canadian Aviation Safety Board (CASB), expressed concern about the lack of survival equipment on small commercial passenger-carrying aircraft during winter operations, and recommended that:
The Department of Transport, having due regard to space and weight limitations while benefitting from advances in available lightweight materials:
a) prescribe a minimum list of survival equipment suitable for post-accident winter conditions; and
b) require the carriage of prescribed survival equipment on aircraft operating during the winter on passenger-carrying flights under the provisions of Air Navigation Order Series VII, Numbers 3 and 6. (CASB 86-20, issued in 1986)
TC agreed with the recommendation. However, no significant revisions were made to the ANOs, and the provisions for waivers against the carriage of all or some of the survival equipment specified in the ANOs were retained. Thus, the company in this occurrence was not required to carry sleeping bags in the survival kits. Following another accident near Bonaventure, Quebec, in 1989, in which three of the five surviving passengers on a small commercial aircraft suffered serious injuries and the contents of the aircraft first aid kit were inadequate, the TSB recommended that:
The Department of Transport reconsider the feasibility and practicality of including a first aid kit specifically equipped for post-accident survival in the aircraft survival kit required by Air Navigation Order (ANO) Series V, No. 12. (TSB A91-23, issued in 1991)
In response, TC acknowledged that the requirements for first aid supplies might be insufficient for post-accident use. TC was, however, of the opinion that it was not practical to include additional first aid supplies in the survival kit, since some operators were able to waive the requirements for survival kits. An alternative was to improve the contents of the existing first aid kits. As such, the new CARs will require that the contents of the first aid kit(s) on aircraft be equal to those specified in the Aviation Occupational Safety and Health (OSH) regulation. OSH guidelines are used for the safety of employees at their work place, and, in this sense, the first aid kits will be an improvement. However, in the Board's view, the first aid kits will not fulfil on-site medical needs immediately following an aircraft crash and during the wait for rescue. While data indicate that only a few aircraft accident survivors have had to spend considerable time awaiting rescue, the often harsh Canadian climate can very quickly put the lives of survivors in jeopardy. While the SARSAT(4) system greatly improves rescue response times over those of just a few years ago, the success of this system depends on a functioning ELT in the accident aircraft. Department of National Defence Search and Rescue statistics indicate that, including those instances where the ELT has not been armed, ELTs have not activated in 40 to 50 per cent of all aircraft accidents(5). In 1991, TC commenced a two-year trial on a new generation of ELTs; however, ELTs designed to the standard of the improved TSOs are still not required in Canada. As previously stated, the new CARs contain some revisions to the orders affecting post-crash considerations. CAR 602.61 states that sufficient survival equipment, given the season of the year, the geographical area, and anticipated seasonal climatic variations, must be carried for each person on board the aircraft. As with the previous ANOs, however, the CARs also provide for exceptions to the basic requirements. The Board recognizes the need for waivers given the wide differences in aviation operating conditions that can be encountered across Canada; it would not be practical to expect every air carrier to outfit its aircraft with all the equipment specified in the CARs under all conditions. However, the Board is concerned about the potential misapplication of any exemptions. For example, the CARs state that the carriage of survival equipment is waived on all multi-engine aircraft flying on designated air routes south of the Arctic Circle. Apparently, many air taxi and commuter operators--generally flying smaller, older multi-engine aircraft, operating between remote locations on self dispatch systems with minimal flight following, and comprising a segment of the commercial passenger industry having a higher accident rate than the industry as a whole--would not be required to carry survival equipment on their aircraft. Aviation accident data indicate that there is a higher risk to safety in commercial aviation from factors related to human performance, such as those found in this occurrence, than from engine failures in single-engine aircraft (a factor on which the cited exemption seems to be based). The Board believes that an approach for the granting of exemptions using risk indicators could better determine the survival equipment requirements on a carrier-by-carrier basis, thus ensuring that sufficient survival equipment is carried on board those aircraft where the potential need is greater. This CFIT accident was typical, in that it occurred about 2 1/2 miles from the airport on approach. In Canada, 44 per cent of CFIT accidents occur during the approach phase. Fortunately, this accident occurred during the hours of daylight, and the ELT worked, facilitating the ground search. Night or bad visibility might have compromised the outcome, given the severe winter conditions. Notwithstanding previous recommendations made by the Board and by regulatory and industry working groups, and the improved TSOs for ELTs, safety deficiencies affecting post-crash survivability continue to exist, as exemplified by this accident. Without appropriate guidelines for the carriage of enhanced first aid kits for post-crash use, and for the granting of waivers regarding the carriage of survival equipment, and without the immediate upgrading of ELT requirements for all commercial passenger-carrying aircraft, accident survivors will continue to be put at risk as a result of delayed rescue, lack of preparedness for harsh climatic conditions, and/or inadequate first aid treatment. Therefore, the Board recommends that:
The Department of Transport, using accepted risk management methodologies, create carrier- specific requirements for the carriage of first aid kits, survival equipment, and upgraded ELTs on all commercial aircraft. A96-08
Survival Equipment
The current requirements for survival equipment, contained in ANO V; No. 12, the Carriage of Emergency Equipment and Radio Communication Systems in Sparsely Settled Areas Order, applied only to operations in sparsely settled areas. The new Canadian Aviation Regulations (CARs) address survival equipment for all aircraft operations. Except for certain conditions of lower risk as outlined in section 602.61 (2), which were reviewed as part of the Canadian Aviation Regulation Advisory Council (CARAC) process, section 602.61 of the new CARs requires that an aircraft flying over land must carry on board survival equipment sufficient for the survival on the ground of each person on board, given the geographical area, the season of the year and the anticipated seasonal climatic variations. This equipment must provide the means for starting a fire, providing a shelter, providing or purifying water and a means of visually signalling distress. Except for the means for starting a fire, aircraft that must carry life rafts over water must provide the same amenities.
In accordance with these regulations, the requirement for survival equipment becomes carrier specific in that the carrier must demonstrate to Transport Canada that its survival kit meets the intent of the Regulation. The equipment must be inspected regularly in accordance with the inspection schedule set out in the carrier’s operations manual. For flights over land, the operations manual must show how compliance with the CARs will be achieved, a list of survival equipment and information on how to use it must be on board, a survival manual appropriate for the season and climate must be available, and crew members must be trained in the operation and use of all emergency equipment. For flights over water where life rafts are carried, the rafts will be equipped with a survival kit containing the items listed in subsection 724.84(2) of the CARs.
First Aid Kits
Paragraph 2.5.2 of the Analysis section of the report states that although the first aid kit met the regulatory requirements, its contents were inadequate to deal with the types of injuries sustained in this accident.
The new CARs stipulate that the first aid kit shall meet the Aviation Occupational Safety and Health Regulations (OSH), Part X, Schedule II, for a type A or type B kit. The Aviation OSH Regulations clearly identify the specific items required as well as the quantities of each. The new CARs now identify the number of kits that must be carried, which varies with the number of passengers for which an aircraft is configured. For aeroplanes with more than 100 passenger seats, an approved emergency medical kit must be carried as well and must contain as a minimum the items listed in the CARs. This requirement is based on the accepted risk management methodology that statistically for every 100 passengers there will be a person with medical credentials sufficient to successfully handle the medical supplies such as specific medicines (Epinephrine, Nitroglycerin tablets) and equipment (syringes and needles).
In addition to the above, Transport Canada has also established an Aviation OSH Regulations Review Working Group. This Working Group will be tasked to review the adequacy of the contents of first aid kits to deal with injuries to survivors of a crash.
Emergency Locator Transmitter (ELT)
Transport Canada feels that the adoption of the TSO C126 ELT would solve many of the problems with ELTs currently in use. The use of effective ELTs is currently being discussed within the Federal Aviation Administration (FAA) Aviation Rulemaking Advisory Committee (ARAC) of which Transport Canada is a member. The Part VI Technical Committee of the CARAC has been advised of the overall ELT issue. After the ARAC has completed its activities on the subject, the TCA Regulatory Committee will consider assigning this issue to the Part VI Technical Committee to study the ARAC findings in the Canadian context.
(4) Search and Rescue Satellite system capable of detecting signal transmissions from activated ELTs.
(5) In 1990, as a result of a Cessna 402 occurrence at Charlo, New Brunswick, in which the ELT did not function as intended (A88A0047 refers), the TSB identified a safety concern regarding the fact that such equipment, intended for emergency use, had such a high rate of failure.
A95H0012 - VFR into IMC - Controlled Flight into Terrain - Western Straits Air de Havilland DHC-3 (Turbine) Otter C-FEBX - Campbell River, British Columbia 7 nm NW - 27 September 1995
Synopsis
The aircraft was en route from Triumph Bay (40 nm south of Kitimat), British Columbia, to the Campbell River Airport. Approaching Campbell River, the pilot requested and received a special visual flight rules (SVFR) clearance to enter the Campbell River control zone. While on an intercept heading for the final approach and in straight-and-level flight, the aircraft crashed into the side of a mountain. The pilot and seven of the passengers received fatal injuries; the other two passengers received serious injuries.
The Board determined that the pilot progressively lost situational awareness while attempting to navigate in conditions of low visibility or in cloud and was unaware of the rapidly rising terrain in his flight path. Contributing to this accident were the existing visual flight regulations and the prevailing industry attitudes and practices which did not provide adequate safety margins. Contributing to the severity of the injuries was the detachment of the passenger seats at impact.
Safety Action Taken
(as presented in the TSB Report)
Seating and Restraint System
Subsequent to this accident, the TSB issued a safety advisory to Transport Canada (TC) identifying a concern that seating and restraint systems of some aging aircraft do not provide adequate protection to passengers in the event of a crash or forced landing. Aircraft systems are being modernized to extend their useful lives for commercial passenger-carrying operations, but these upgrades seldom include the improved passenger safety provisions consistent with contemporary standards. Thus, the TSB suggested that TC take a more systems-oriented approach in approving such life-extension programs.
Engine Condition Trend Monitoring
During the investigation, it was established that the ECTM program, which formed part of the approved maintenance program for the turbine engine installation on C-FEBX, had not been used as per Transport Canada's approval. It was also determined that some of the TC airworthiness inspectors responsible for the Western Straits Air maintenance system were not trained in trend monitoring programs. The TSB subsequently advised TC of this issue and suggested that TC consider adding ECTM to the airworthiness inspectors' training curriculum.
Safety Action Required
(as presented in the TSB Report)
Air Regulations and Air Navigation Orders established under the Aeronautics Act, such as those governing VFR and SVFR flights, prescribe operating limits. Such limits are designed to provide operational flexibility, while ensuring minimum acceptable safety margins. Such regulations are influential elements in determining industry operational practices and in establishing the level of safety of the transportation system.
The Campbell River accident raises questions regarding the feasibility of VFR and SVFR flights in marginal weather conditions, considering pilots' limited capability to recognize deteriorating visibility, the adequacy of the margin of safety afforded by VFR and SVFR regulations, and the level of operators' awareness of the risks associated with commercial operations in marginal weather conditions.
Visual Flight - Margin of Safety
In its 1990 Report of a Safety Study on VFR Flight into Adverse Weather (90-SP002), the Board made several recommendations to the Department of Transport concerning visual flight rules. In recognition of the problems of safely maintaining visual references in mountainous terrain, the Department of Transport subsequently increased VFR visibility minima in designated mountainous areas from one mile to two miles.
At the time of this occurrence, the aircraft was operating under VFR in uncontrolled airspace within a designated mountainous area. To be in compliance with VFR, the aircraft was required to be flown with reference to the ground or water and remain clear of cloud; the pilot was required to stay within sight of the surface of the earth at all times, and was required to ensure a minimum flight visibility of two miles. Under SVFR in the Campbell River control zone, the same restrictions would apply except that the minimum flight visibility would be one mile. There are no minimum ceiling requirements for either SVFR flight or VFR flight in uncontrolled airspace below 1,000 feet agl.
The accident record continues to show that VFR CFIT accidents occur primarily when operations are being conducted in marginal weather and/or dark night conditions. Interviews with flight crew and operators obtained during this investigation indicate that it is common practice in the industry to continue flight operations at the minimum visibility requirements for VFR and SVFR. When operating in conditions that include low ceilings and visibilities, pilots often pick their way through the weather while trying to stay visual. Flight in marginal weather presents a high risk of inadvertent entry into conditions where visual reference is insufficient for the maintenance of aircraft control, terrain and traffic avoidance, and accurate navigation. There are substantial grounds for questioning a pilot's ability to safely complete flights under such conditions.
Visual Depth Perception. In perceiving both depth and distance, humans interpret several visual cues in such a way as to generate a three-dimensional image in the visual cortex of the brain:
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Linear Perspective The distances between distant images appear to be less than those separating near images. For instance, railway tracks appear to converge in the distance. Knowing that the tracks remain a fixed distance apart, the convergence is interpreted as a distance cue.
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Clearness In general, the more distant an object, the less clearly it is seen. Further, a mountain on a hazy day appears more distant than it would on a clear day.
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Interposition When an object partially obstructs the view of another object, the first object appears nearer.
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Shadows Humans are used to perceiving objects with light sources situated above them; this information is used to give objects a spatial orientation.
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Gradients of Texture Generally, the texture of a scene appears finer and there is less detail as distance increases; conversely, foreground appears coarser and there is more perceptible detail.
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Movement When the head moves, objects move in relation to oneself and to each other. Objects beyond the eyes' visual fixation point move in the same direction as the head. Objects nearer than the point of visual fixation appear to move in the direction opposite to the movement of the head. The amount of movement is less for distant objects than for near objects.
Assessing Distance in Marginal VFR. When visibility is poor, the cues to perceive distances of objects are diminished. Without these cues, consistent, accurate judgement of distance is improbable, even in a relative sense.
Humans tend to be poor judges of distance in absolute terms; they can best judge distance in relation to some fixed marker. Thus, trained weather observers use known distances from ground features to establish ground visibility. In the mountainous area of Vancouver Island, distance cues or markers are much less likely to be available. Reliably judging one mile of visibility from a moving aircraft is arguably a task beyond human capability.
Another factor that could detract from a pilot's ability to judge whether the one-mile visibility requirement is being met relates to the angle of flight visibility being considered. The primary requirement of visual flight is that the aircraft shall be flown with reference to the ground or water. When an obscuring phenomenon like fog is present, the reduction in visibility at low altitude can be much less looking downward than looking forward. The survivors of the Campbell River crash reported that they were able to see the ground in the Campbell River area; however, obstacle avoidance requires forward visibility, which was not available. A reasonably clear view of the ground in marginal conditions could lead a pilot to believe that the one-mile forward flight visibility requirement was being met. Clear downward visibility would likely be an influential cue to the pilot, even though not necessarily a reliable or accurate cue.
Aircraft flight control and navigation may be conducted exclusively by visual reference to cues outside the cockpit, by reference to aircraft instrumentation, or by varying combinations of external and internal references. In this accident, the pilot was apparently attempting to avoid terrain and navigate by using a combination of external references and aircraft instrumentation.
In Canada, air-taxi operations are often conducted fully or in part under visual flight rules. Over an eleven-year period (01 January 1984 to 31 December 1994), there were 70 accidents involving commercially operated aircraft not conducting low-level special operations, where the aircraft were flown into terrain, water, or obstacles, under control, while the crew had no awareness of the impending disaster. In over half of the occurrences, the crew was attempting to see the ground in order to fly visually, although the conditions apparently precluded visual flight. These 70 CFIT accidents involved pilots with the full range of experience, indicating that experience does not appear to be a factor in reliably coping with conditions of marginal visibility. Several recent commercial accidents (A95P0268, A95C0026, A95Q0104) in which VFR flights were attempted in flight conditions which did not allow the pilots to visually navigate and/or avoid collision with terrain illustrate that the same issues continue to be factors in this type of occurrence.
The Board understands that the present VFR and SVFR requirements are the result of years of evolution in committee proceedings; however, these committees seldom include representation from the scientific community, and therefore do not take into account the research available on such aspects as the human visual system and normal human information processing capabilities. Safe operations in VFR and SVFR conditions depend almost entirely on the pilot's ability to assess flight visibility and immediately recognize any deterioration. When flying in the minimum weather conditions allowed by VFR and SVFR, recognition of deteriorating visibility can be virtually impossible, particularly when combined with other factors such as high workload, variable weather conditions, poor light conditions, or limited outside visual cues. Therefore, the Board recommends that:
The Department of Transport sponsor research to establish on a scientific basis the ability of pilots to assess distances, make appropriate decisions, and control aircraft without reference to aircraft instruments in the marginal visibility conditions of VFR and SVFR minima. (A96-09)
Transport Canada's Response:
Transport Canada (TC) will sponsor research to establish on a scientific basis, the ability of pilots to assess distances, make appropriate decisions, and control aircraft without reference to aircraft instruments in marginal visibility conditions of VFR and SVFR minima. In addition, human factors expertise will be utilized to ensure that the scientific data is linked to the unique stresses found in a pilot’s working environment that may impact on a pilot’s ability to make proper decisions and to exercise sound judgment.
Safety Action Required
(as presented in the TSB Report)
Adequacy of Current Regulations. Under current regulations, the requirement to fly VFR is that the aircraft shall be flown with visual reference to the ground or water. The new Canadian Aviation Regulations state that the aircraft shall be operated with "visual reference to the surface." Neither regulation defines just what constitutes "visual reference to the surface"; nor is any rationale provided as to what a pilot is expected to do based solely on that visual reference. Nevertheless, it is the Board's understanding that the basic tenet of VFR flying in Canada is that the pilot be able to maintain control of the aircraft, avoid obstacles and other air traffic, and navigate solely through the observation of references external to the aircraft. Given that the 70 CFIT accidents involving commercially operated aircraft referred to above claimed 106 lives and left 23 persons seriously injured, the Board believes that the regulatory requirements for visual flights and the understanding and the application of these requirements by pilots (even experienced and instrument-rated pilots) are inadequate. The severe consequences and high probability of error in assessing flight visibility suggest that these regulations are particularly inappropriate in the context of commercial passenger-carrying operations. Therefore, in the light of the findings of the research recommended above, the Board recommends that:
The Department of Transport evaluate the adequacy of the margin of safety afforded by current VFR and SVFR regulations--particularly for commercial passenger-carrying operations. (A96-10)
Transport Canada's Response:
Provisions that did not exist in the former regulatory structure impose additional requirements on VFR operations; these are contained in the Canadian Aviation Regulatory (CARs) which came into effect on October 10, 1996, and are considered adequate.
CAR 703.29 states:
"No person shall commence a VFR flight unless current weather reports and forecasts, if obtainable, indicate that the weather conditions along the route to be flown and at the destination aerodrome will be such that the flight can be conducted in compliance with VFR."
Identical provisions are also contained in CARs 704 and 705.
Nevertheless, Transport Canada will commission a study to assess the adequacy of the current means for regulating operations in reduced visibility under VFR and SVFR. In particular, the study will concentrate on the human factors issues to determine if alternate means beyond, or in addition to, further regulatory action may prove more effective in reducing the incidence of accidents in low visibility.
Application of Regulations. Regardless of the prescribed minima, the variability of flight visibility and the subjectivity in assessing it from a moving aircraft make enforcement of visibility requirements implausible in most circumstances. Apparent differences of opinion among pilots and operators as to the application of the prescribed minima further exacerbate the situation. Education and training seem to offer the most scope for practically implementing the visibility requirements. Yet, commercial aircraft accidents in adverse weather continue, despite frequent emphasis in TC safety newsletters and presentations on the importance of adhering to established VFR limits. In view of the occurrence record involving experienced as well as instrument-rated pilots, the Board believes that there is inadequate understanding throughout the aviation community of the risks and the consequences of operating in marginal weather conditions. A false sense of security develops when pilots and their peers repeatedly succeed in getting through marginal conditions--without incident. The Board believes that many CFIT accidents could be prevented if dangerous situations were recognized as conditions deteriorate. Therefore, the Board recommends that:
The Department of Transport develop and implement a targeted national promotion campaign aimed at raising commercial operators' awareness of the inherent risks associated with flight operations in marginal VFR flight conditions. (A96-11)
Transport Canada's Response:
Transport Canada also is concerned about the incidence of weather related accidents. Our aviation newsletters, aviation safety management programs, decision-making course, safety awareness education programs and safety videos have focused extensively on the behavior needed to avoid such accidents. All of these programs, courses and videos are available nationally. In further support of these programs, the department has recently produced and distributed the video "Situational Awareness - Preventing controlled Flight Into Terrain".
In April 1982, a national promotional campaign - "Weather Related Accident Campaign" was completed. Issues and recommendations resulting from this campaign such as, compulsory currency requirements for all flight crew, and limitations on flight and duty times have been addressed with the implementation of the CARs. The recommendation for the development of a Company Safety Officer system was implemented some time ago under the Company Aviation Safety Management Program and is regulated under the CARs for Airlines. While considered successful overall, the "Weather Related Accident Campaign" had little impact upon the commercial/business aviation accident rate.
Additionally, in response to a requirement made by the International Civil Aviation Organization (ICAO) in November 1989, for compulsory training in human factors for all air crew, the requirement has been included in the Personnel Licensing and Training Standards for Part IV of the CARs and three new manuals on "Human Facotrs for Aviation" - will soon be available. These manuals will cover such subjects as Decision Making and Judgment, Stress, Orientation and Disorientation.
Air Taxi operations are under review with formation of the Safety of Air Taxi Operations (SATOPS) Task Force. The Task Force will conduct meetings in all regions, inviting participation from air operators, pilots, aircraft maintenance engineers, air traffic service personnel and Regional and Headquarters representatives. The focus of the Task Force will be on what the air operators are doing to prevent accidents within their companies, what they are doing to promote safety within their companies and to identify what can contribute to unsafe operating practices, both within the company and external to the company. Transport Canada will undertake new initiatives in response to recommendations arising from the SATOPS Task Force, and consideration for a targeted national promotion campaign will be done at that time.
Transport Canada will review the distribution policy of the multiplicity of current programs designed to encourage safe operating practices in order to insure that these programs are brought to the attention of the commercial operators holding Operating Certificates for Aerial Work, Air Taxi, Commuter or Flight Training. The target audience within these commercial operations would be the management level to emphasize to them the importance of encouraging the development of an environment in which flight crews under their direction are confident of management support to avoid the inherent risks associated with flight operations in marginal VFR flight. Operators would be encouraged to voluntarily develop a Company Aviation Safety Management Program and appoint a Company Aviation Safety Officer.
Transport Canada will continue to provide education on flight into deteriorating weather through aviation newsletters, aviation safety management programs, decision-making courses, safety awareness education programs and safety videos etc.
Safety Action Required
(as presented in the TSB Report)
Pilot Decision Making
In accordance with standard investigation practice, accident pilots' decision-making processes are analyzed. The temptation to judge the quality of a pilot's decisions by the outcome, however, must be guarded against. Fairness to the individual and the advancement of transportation safety require that the actions of the pilot be understood within the context in which pilots typically are operating.
Cockpit decisions can be conceived of as having two components: situation assessment and selection of a course of action. Thus, the difficulty involved in decision making depends primarily on "the degree of clarity of the cues signifying the problem and the nature of the response options available in the situation." (4)
Cues, or information about the situation, can vary between clear and ambiguous. In situations such as emergency procedures, the cues are so strong that decision options are prescribed and the response is automatic. Sometimes, once a situation is defined or interpreted, the pilot must choose among options, or schedule tasks in the most appropriate order for the conditions. This represents a higher level of complexity. The most demanding decision making involves those situations where there are no pre-determined options. In these cases, pilots must develop their plans by using both their knowledge of the system and their assessment of the situation. The more complex and difficult a decision is, regardless of whether the difficulties are in the situation assessment component or in the response selection component, the greater the likelihood of a decision that is less than ideal. Consequently, decision tasks in the cockpit differ in the degree to which they are well-structured and thus have an agreed-upon "best" solution.
The accident pilot was familiar with the area and the aircraft. Low ceilings and poor visibility are common occurrences in the area and he had flown many hours in similar meteorological conditions. As he approached Campbell River, the ceiling at the airport was low (about 300 feet), but over the water, the clouds were about 1,000 feet above the surface.
The decision making in this occurrence required that the pilot assess the situation and choose between continuing to the airport or landing on the water at Tyee Spit, which would undoubtedly have entailed some inconvenience for the passengers. He may also have considered climbing and requesting an IFR approach, for which he was qualified and equipped.
As the pilot approached the control zone, the weather in his immediate area was above ceiling and visibility minima. The Campbell River airport reported a ceiling of 300 feet and two miles visibility, but the ceiling had been varying between 300 and 500 feet through the day and an aircraft ahead reported sighting the Campbell River runway from 900 feet asl. The pilot had an SVFR clearance which only required a flight visibility of one mile and the aircraft to remain clear of cloud. The fact that the aircraft was instrument equipped, and that the pilot was qualified for instrument flight and experienced in conducting instrument approaches into Campbell River would likely have further contributed to his confidence in continuing to the airport. The course of action selected by this pilot, based upon the existing regulations and his experience, would have been taken by many pilots with similar experience.
Once the decision to try to land at the airport was made and the aircraft turned inland, the clarity of the visual cues deteriorated. At about 2 1/2 miles from the airport, the pilot apparently changed his plan and attempted to set up an approach from the same direction as the aircraft which had reported sighting the runway from 900 feet. It is doubtful that the pilot would modify his plan as he exited from the control zone; in principle, though, his visibility criteria increased from one mile for SVFR to two miles for VFR in designated mountainous terrain as he crossed an imaginary line at the boundary of the control zone. It is likely that his attention was focused on controlling the aircraft and his workload was heavy at this point, so that both the transition to uncontrolled airspace and the significance of it were probably not recognized at a conscious level. It appears as though he did maintain visual reference with the ground during this time.
In the light of the outcome, changing his plan and returning to Tyee Spit would have been more prudent; but the cues available to the pilot were apparently not compelling enough to change his mental model, or assessment of the situation. Once individuals select a particular course of action, it takes very compelling cues to alert them to the advisability of changing their plan. Indeed, there is a tendency to use these cues to confirm the validity of the intended plan of action (5). This pilot had control of the aircraft, was maintaining visual contact with the ground, and was able to navigate, probably with the aid of instruments. These cues would be sufficient to lead many professional, safety-conscious pilots to continue the approach to the airport.
A recent analysis by the National Transportation Safety Board (NTSB) in the US involving 37 accidents showed that, when faced with Go/No-Go decisions, 66% of the crews continued with their current plan in the face of cues which suggested they should have abandoned it. "However, in many of these cases the cues were ambiguous and it was difficult to assess with great confidence the level of risk inherent in the situation." (6)
Inexperience, lack of knowledge, imprecise guidelines, and ambiguous cues will continue to make some pilot decision-making circumstances difficult. However, strategies to maximize the quality of decisions can be learned, and include such things as situation assessment, risk assessment, planning, resource management, communicating, and the identification of special skill requirements. (7)
Of note, increasing the SVFR minima could change the nature of decisions to be made in occurrences like the Campbell River accident. If there had been a greater minimum visibility requirement, or rules requiring a combination of ceiling and visibility, the pilot would have been faced with an easier decision. Had the previous SVFR rules been in force, the only option would have been to land at Tyee Spit. Thus, the need to re-assess the adequacy of current VFR weather minima (recommended above) should be considered in the light of normal pilot decision-making processes.
The accident pilot was operating in an environment which accepted as "normal operations" flights into marginal weather conditions, when other options, such as landing at Tyee Spit, were available. Typically, pilots involved in VFR CFIT accidents have not had any special training in decision making. At the same time, pilots flying in small air carrier operations are arguably the most exposed to such ambiguous situations with the least decision-making support. They often operate as single-person crew into a variety of unfamiliar locations with minimal infrastructure and are self- dispatched, and the aircraft do not usually possess sophisticated instrumentation or control systems.
The Board has previously recommended that Transport Canada develop and implement a means of regularly evaluating the practical decision-making skills of commercially employed pilots in small air carrier operations (TSB A90-86). TC's response in part stated:
It has been Transport Canada's position that the benefits of this training were intrinsic in the enhanced performance of the pilot and that a properly planned and executed Pilot Proficiency Check would provide a practical and realistic assessment of a pilot's ability to make reasoned and timely decisions when faced with a simulated emergency situation. We will continue to keep abreast of developments in the field of decision-making training and assessment and will not hesitate to introduce improvements in our present system should they become available.
National and regional carriers have broadly embraced the concepts of Cockpit Resource Management (CRM) and Pilot Decision Making (PDM) training, and under the new Canadian Aviation Regulations, airline operators will be required to complete initial and recurrent CRM training. However, for other commercial operators, formal programs are being introduced on a voluntary basis. The Board believes that, given the natural human limitations in interpreting distances in marginal visibility conditions, natural human tendencies in complex decision making in the presence of changing and ambiguous cues, and the CFIT accident record involving small commercial operators, further counter-measures are required to facilitate safe crew decision making. Therefore, once again, the Board recommends that:
The Department of Transport require that pilots involved in air-taxi and commuter operations receive specialized training, including skills development, in making prudent decisions under deteriorating operational conditions. (A96-12)
Transport Canada's Response:
Transport Canada, in consultation with the aviation community through the Canadian Aviation Regulation Advisory Council (CARAC) process, will task the Commercial Air Services Technical Committee to study and develop whatever additional specialized training requirements may be required so that pilots involved in air taxi and commuter operations are fully capable of making prudent decisions under deteriorating conditions.
FOOTNOTES
(4) Orasanu, Dismukes, Key, and Fischer, Proceedings of the HFES Meeting 37th annual meeting, Seattle, Washington, 1993.
(5) James Reason, Human Error (Cambridge: Cambridge University Press, 1990)
(6) Judith Orasanu and Ute Fischer, "Finding Decisions in Natural Environments: The View from the Cockpit." To appear in Naturalistic Decision Making, ed. C. Zsambok and G.A. Klein, (Hillsdale, NJ: Lawrence Erlbaum Associates). Courtesy of the primary author.
(7) Judith Orasanu, "Decision Making in the Cockpit," Cockpit Resource Management, ed. Weiner, Kanki, and Helmreich (San Diego: Academic Press, 1993) 137 - 172.
A95H0015 - Rejected Take-off/Runway Overrun - Canadian Airlines International - McDonnell Douglas DC-10-30ER C-GCPF - Vancouver International Airport, British Columbia - 19 October 1995
Synopsis
Canadian Airlines International Flight 17 was on a scheduled flight from Vancouver International Airport to Taipei, Taiwan. On board were 4 flight crew, 8 cabin crew, 2 interpreters, and 243 passengers. During the take-off on runway 26 and approximately two seconds after the V1 call, the crew heard a loud bang and felt an airframe shudder and considerable vibration, later attributed to an engine stall. The captain called for and initiated a rejected take-off. The aircraft could not be stopped on the runway, and the nose-wheel gear collapsed as the aircraft rolled through the soft ground beyond the end of the runway. The aircraft came to rest in a nose-down attitude approximately 400 feet off the declared end of the runway. Six passengers were slightly injured during the emergency evacuation of the aircraft.
The Board determined that engine number 1 lost power at a critical point in the take-off and that the rejected take-off was initiated at a point and speed where there was insufficient runway remaining to stop the aircraft on the runway. Contributing to this occurrence were the misidentification of the cause of the loud bang and the lack of knowledge regarding the characteristics of engine compressor stalls. Contributing to the engine power loss was a delay between the collection and analysis of the engine monitoring data.
Safety Action Taken
(as presented in the TSB Report)
Engine Monitoring
Since the occurrence, CAI has taken steps to enhance the timeliness of its processing of engine trend monitoring data. In March 1996, CAI completed a program, begun before the occurrence, of equipping all of its DC-10 aircraft with an Aircraft Communications and Reporting System (ACARS), which can relay the flight data to ground stations. An interface program will be installed to acquire the airborne data and to feed this data through a ground-based personal-computer ADEPT program at CAI. The new procedures will require flight crews, using ACARS, to transmit engine readings to the ground station at the time that they are recorded. This new system will provide a near real-time acquisition, processing, and evaluation of the engine trend monitoring data.
Following the accident, the TSB forwarded a Safety Advisory to Transport Canada (TC) suggesting that other users of engine trend monitoring systems be advised of the safety benefits associated with timely analysis of engine data. TC subsequently published an article regarding jet engine fault monitoring in its Maintainer newsletter and is planning a similar article for the Feedback newsletter.
Evacuation Slide/Raft Cover Hinge Springs
Following the discovery of the problem with the hinge springs, CAI conducted a special inspection of the slide/raft covers on all its DC-10 aircraft, and found similar problems. As a result, CAI has begun retrofitting its DC-10 aircraft with larger hinge springs as recommended in McDonnell Douglas MD-11 Service Bulletin 25-148.
TC has sent a letter to the Federal Aviation Administration (FAA), requesting that the FAA urge McDonnell Douglas to address the problem of the DC-10 chute/raft cover hinge springs through action similar to that recommended in Service Bulletin 25-148 for the MD-11.
The FAA and McDonnell Douglas agreed with this course of action, and Service Bulletin DC10-25-367, applicable to DC-10 chute/raft cover hinge springs, has been issued by McDonnell Douglas.
Take-off Performance System Changes
American Airlines Corporation (AMR) has stated that software changes are being developed to correct the Take-off Performance System (TPS) program errors in calculating engine thrust when pressure altitudes are below sea level. AMR is also amending the TPS program to make it possible for crews to obtain performance data for power settings other than the TPS selected settings.
The TSB is investigating occurrences in which errors in ground-based aviation related software adversely affected safety. The adequacy of current quality assurance methods for such software is being examined.
Passenger Recovery
The Vancouver International Airport Authority reports that, in response to the delays in recovering the passengers of Flight 17 from the accident site, the Airport Duty Manager Incident Call Out/Checklist has been revised. The checklist for the Airport Duty Manager in the Emergency Operations Centre now reflects the need to call the Vancouver International Airport Authority Ground Transportation Department to acquire immediate bus transportation. Buses will be requested from the Airport Authority's fleet of shuttle buses normally used for transportation to and from public and employee parking lots. Using the Airport Authority shuttle buses is meant to complement the efforts of the individual air carriers, who remain responsible for transporting the passengers from the accident site to the terminal building.
Spoiler Extension During Rejected Take-offs
As a result of CAI's assessment of the potential delay resulting from relying on the selection of thrust reversers to deploy the spoilers to activate the auto-brake system, CAI has redrafted its DC-10 Flight Crew Operating Manual (FCOM) rejected take-off checklist to indicate that the second officer "deploys the spoilers without command." CAI's DC-10 Standard Operating Procedures on rejected take-offs have also been amended to direct the second officer "as soon as the throttles are closed to pull the spoiler handle full aft and up without command."
MEL Changes
As a result of CAI's assessment of the potential adverse effect of a disabled thrust reverser on a high-weight rejected take-off, CAI redrafted its DC-10 MEL Item 78-01 Thrust Reverser/Fan Reverser. TC has approved CAI's MEL amendment which specifies that the dispatch of DC-10-30 aircraft within 20,000 pounds of its runway-limit weight or above 572,000 pounds with a thrust reverser disabled will require the concurrence of the captain and chief pilot and their favourable assessment of the take-off conditions and environment.
Communications Limitations
CAI amended its DC-10 FCOM and crew training program to include information about the unavailability of audio panel 2 when the aircraft emergency power switch is ON.
The TSB sent a Safety Advisory to TC suggesting that they liaise with McDonnell Douglas and the FAA concerning dissemination of information regarding the communication limitations associated with the use of emergency power on the DC-10.
Definition of V1 in DC-10 FCOM
The wording in the CAI DC-10 FCOM may be ambiguous in that it implies that some time beyond V1 is available before the pilot needs to initiate the rejected take-off. Given the potential for pilots to misconstrue the definition of V1 in the FCOM, and given the potential for adverse consequences as a result of rejecting a take-off after V1 (in a field-length-limited context), the TSB forwarded a Safety Advisory to CAI. The Advisory suggested that CAI might wish to amend the definition of V1 in the DC-10 FCOM and review the V1 definition in other pilot reference materials, including those for other CAI aircraft.
Safety Action Required
(as presented in the TSB Report)
Engine Malfunction Recognition
The captain did not recognize the loud bang as a symptom of a high bypass ratio engine compressor stall and thought that the noise might have been caused by a bomb. Consequently, he decided to reject the take-off even though the speed was above V1. Although the flight crew members were all very experienced pilots and had taken simulator and ground training throughout their careers, they had not been trained to recognize a loud bang as a symptom of a high bypass ratio engine compressor stall, and none of the crew members noticed the cockpit indications of power loss.
Rejecting a take-off at a speed above V1 during a field-length-limited take-off places an aircraft at more risk than continuing the take-off, and should not be attempted unless the pilot has reason to conclude that the airplane is unsafe or unable to fly. The FAA's Takeoff Safety Training Aid states that "in order to eliminate unnecessary RTOs, the crew must differentiate between situations that are detrimental to a safe take-off, and those that are not." Also, a Boeing report entitled Engine Plus Crew Error Events indicates that positive recognition and correct identification of engine malfunctions appear to be significant contributors to the outcome of engine-plus-crew-error events. If pilots do not consider a loud bang as a symptom of a possible compressor stall, they may assume that the noise was caused by a bomb (a much less likely event) and unnecessarily reject the take-off.
Crew errors are often associated with engine failures that create loud noises. The Boeing report indicates that the majority of engine-plus-crew-error events involved engine malfunctions that generated loud noise. The report further indicated that the number of such events involving high bypass powered aircraft had steadily increased over the last five years covered by the study. Few resources are available to flight crews to aid in the quick identification of engine failure conditions. Neither engine manufacturers nor aircraft manufacturers have specific information available on the characteristics of high bypass ratio engine compressor stalls. The Boeing report observes that there is currently no flight crew training for positive recognition and correct identification of engine failure conditions; the noises, vibration, and other "cues" of real engine failures are not simulated in the vast majority of flight crew training simulators. In light of the risks associated with unnecessary rejected take-offs, the Board recommends that:
The Department of Transport ensure that flight crews operating high bypass ratio engines can correctly identify and respond to compressor stalls or surges. (A96-13)
Transport Canada's Response:
Flight crew training encompassing recognition and response to engine malfunctions is a part of initial and recurrent training. All flight crews that operate high bypass ratio engines accomplish this training in approved simulators. Although there are varying levels of simulator sophistication, most generate representative sounds that are as real as empirical data permits. Until such time that engine and airframe manufacturers develop parameters for all the different types of compressor stalls, Transport Canada considers this training to be both reasonable and adequate.
Transport Canada is currently following the work of the Aerospace Industries Association (AIA) propulsion committee which has been formed to address issues related to "Propulsion System Malfunctions Plus Inappropriate Crew Responses" and Transport Canada has been invited to help form the focus of the group. Based on the results of these initiatives, Transport Canada will ensure improvements are made to better enable flight crews to properly identify and respond to compressor stalls or surges.
Additionally, Transport Canada will feature this occurrence in its "Aviation Safety Letter" which is distributed to all licensed pilots. The recognition of high bypass ratio engine compressor stalls will be among the items discussed.
Safety Concern
Wet Runway Considerations
Despite the various recommendations, studies, and working groups pertaining to wet runway take-offs over the last 10 years, there is still no requirement for manufacturers to provide approved performance data for aircraft taking off on wet runways, other than for newly certified aircraft. Furthermore, there is no requirement for operators to take into account such data when calculating aircraft take-off performance. Although TC is pursuing these issues, corrective action does not appear to be imminent.
In light of previous recommendations on this subject and in recognition of TC's current related activities, the TSB does not plan to make new safety recommendations on this deficiency at this time. Nevertheless, the Board remains concerned that fare-paying passengers continue to be placed at risk when field-length-limited take-offs are conducted without taking into account reduced braking effectiveness on wet runways
Should you require further information, please contact Aviation Safety Analysis at asi-rsa@tc.gc.ca