A99A0036 - Controlled Flight into Terrain - Provincial Airlines Limited - de Havilland DHC-6-300 Twin Otter C-FWLQ - Davis Inlet, Newfoundland 2 nm NNE - 19 March 1999
Synopsis
The de Havilland DHC-6-300 Twin Otter, serial number 724, was on a defence visual flight rules flight from Goose Bay to Davis Inlet, Newfoundland, with a crew of two on board. The flight encountered instrument meteorological conditions en route and continued to Davis Inlet in these conditions under the defence visual flight rules flight plan. The crew flew a non-precision instrument approach to the airport and, at minimums, executed a missed approach because the required visual references were not established. A second approach was attempted; on the inbound track, the aircraft struck the frozen surface of the Labrador Sea two nautical miles north-northeast of the airport. The first officer was fatally injured, and the captain sustained serious injuries. The aircraft was destroyed.
Safety Action Taken
(as presented in the TSB Report)
After the accident, Transport Canada (TC) conducted a regulatory audit of the operator and increased the frequency of in-flight checks and general inspection of the Goose Bay operation.
Safety Action Required
(as presented in the TSB Report)
Regulatory Safety Oversight
This occurrence investigation uncovered several serious deficiencies in the conduct of the mission. These deficiencies could be symptomatic of a broader and ongoing disregard for regulations and company standard operating procedures (SOPs). Indicators of the deficiencies are as follows: the presence of poor company loading practices at Goose Bay; inadequate company supervision of the Goose Bay operation; non-adherence to aircraft SOPs; and deliberate operation of the aircraft below the minimum descent altitude (MDA) when adequate visual references for landing were not present. These deviations from normal practices were present in day-to-day operations.
The TSB has observed similar deficiencies in the conduct of business in other organizations, as demonstrated by the occurrences referenced in Appendix A--Supporting Documentation to Section 4.2. Common findings relating to regulatory oversight in these accidents, in general terms, were as follows:
- descent below MDA without adequate visual references;
- non-adherence to SOPs;
- operating under visual flight rules when in instrument meteorological conditions;
- operating the aircraft in an overweight condition; and
- inadequate company supervision of operations or maintenance.
Generally, these accidents have been with smaller commercial operators or during operations in remote areas where oversight is difficult. In these operations, there were clear indications that a culture was allowed to exist in which crews and operators operated outside the safety regulations, with catastrophic consequences.
It is recognized that effective safety oversight of smaller or remote operations is a challenging task. Notwithstanding this challenge, the level of acceptable risk should not be greater for passengers and crews who fly on aircraft operated by smaller operators or who operate in or into remote areas, simply because oversight is difficult. It is also recognized that there have been initiatives undertaken by TC to reduce the level of risk in these operations. However, these and other accidents indicate that more needs to be done. It appears that the traditional methods of inspection, audit, general oversight, and regulatory penalties have had limited success in fostering appropriate safety cultures in some companies and individuals; consequently, unsafe conditions continue to exist and unsafe acts are still being committed.
These serious accidents indicate that some operators and crews have disregarded safety regulations and, consequently, put passengers and themselves at an unnecessary and unacceptably high level of risk. In these accidents, findings indicate that, in certain areas of commercial operations, the safety oversight efforts of TC have been somewhat ineffective. Therefore, the Board recommends that:
The Department of Transport undertake a review of its safety oversight methodology, resources, and practices, particularly as they relate to smaller operators and those operators who fly in or into remote areas, to ensure that air operators and crews consistently operate within the safety regulations. (A01-01)
Transport Canada's Response:
Transport Canada is continually reviewing its safety oversight program methodology, resources and practices to meet the challenge of providing effective safety oversight to all areas of the aviation industry in Canada, including the provision of air service to and within remote regions of the country.
Continuous review and improvement of programs and activities is a long established operating principle of Transport Canada. Recent examples include:
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The promulgation of the Canadian Aviation Regulations to replace the Air NavigationOrders in October 1996;
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The Safety of Air Taxi Operations (SATOPS) Task Force launched in 1996 producing a final report in May 1998;
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Flight 2005: A Civil Aviation Safety Framework for Canada published in December 1999; and
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A comprehensive external review of the Civil Aviation safety oversight program completed in July 2001.
Canadian Aviation Regulations (CARs)
The introduction of CARs improved significantly the regulatory framework for small operators. The Canadian Aviation Regulation Advisory Council (CARAC) process incorporates a consultative approach to rulemaking and this feature has improved compliance by producing rules and regulations which are easier to understand and therefore easier for operators to follow. When the operators are actively engaged in the rule-making process they are less likely to ignore the regulations and standards and more likely to develop safe operating practices.
The Safety of Air Taxi Operations (SATOPS)
In January 1996, the Safety of Air Taxi Operations (SATOPS) Task Force was established to examine the operational attitudes and practices prevalent in Air Taxi Operations and to recommend ways to reduce the number of accidents in this sector of the aviation industry.
The final SATOPS report dated May 28, 1998 included 71 recommendations that Transport Canada and the industry have worked to implement.
The majority of accidents cited in the TSB supporting documentation occurred before the SATOPS recommendations were put in place. The number of accidents, on an annual basis, in the air taxi sector has been diminishing steadily, and significantly, since 1998. For instance, the number accidents involving fixed-wing small commercial operators (CAR 703 and 704) dropped from 94 in 1998 to 63 in the year 2000. This would indicate that implementing the SATOPS Task Force recommendations is having the intended effect.
Safety Action Required
(as presented in the TSB Report)
Flight 2005
Recognizing that traditional methods of safety oversight may be approaching the limits of their effectiveness, Transport Canada published in December 1999 Flight 2005: A Civil Aviation Safety Framework for Canada. This framework document identifies six evolving directions which represent the principal adjustments that Transport Canada needs to make to maintain and enhance aviation safety as the industry grows and regulatory resources are likely to remain static:
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Adopting a data-driven approach to enhancing aviation safety. This includes collecting and making more accessible the type of data that will support a proactive approach to safety;
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Using a risk-based approach to resource allocation to support those activities which will achieve the greatest safety benefit;
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Fostering and strengthening partnerships to put into effect the concept that responsibility for safety is shared by the regulator and the aviation community;
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Implementing safety management systems (SMS) in aviation organizations;
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Taking account of human and organizational factors in safety management practices; and
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Communicating effectively with the aviation community on safety.
All these evolving directions are important enhancements to the Civil Aviation Program. Implementing SMS in aviation organizations will be a key step in the process, as SMS will provide the context within which the other initiatives will be realized. The Canadian Aviation Regulation Advisory Council has accepted regulatory changes to require the implementation of SMS in the Airline (Subpart 705) and Business Aviation (Subpart 604) sectors of the industry. Transport Canada is working on developing regulatory changes to require the development of SMS in the Commuter (Subpart 704) and Air Taxi (Subpart 703) sectors
These changes will be very far reaching and Transport Canada is confident that implementing SMS will contribute to the establishment of a safety culture across the industry by requiring management to integrate safety goals into all aspects of enterprise management.
External Review
In November 1999, a consultant firm (DMR Consultant Group) was contracted to conduct a two phased comprehensive review of the Civil Aviation safety oversight program for commercial operations. This review provided a detailed analysis of the safety oversight activities conducted by inspectors. In January 2001, the second phase of the DMR report concluded that Transport Canada is moving in the right direction and provided some recommendations to enhance its performance. In July 2001 further analysis of the results of the DMR report was provided to Transport Canada for consideration. Transport Canada is currently reviewing the results of this analysis to address recommendations and to review the need for further activities.
Conclusion
Through such initiatives as mentioned above, Transport Canada is actively pursuing changes to current regulations and practices with the goal of maximizing effective utilization of available resources by focusing on those activities that will provide the largest benefit to aviation safety. Transport Canada will continue to monitor the aviation environment and will take steps to improve the level of safety in all sectors of the industry, in all regions.
A98H0003 - Interim Aviation Safety Recommendations - Material Flammability Standards Investigation into the Swissair Flight 111 Accident
Interim Aviation Safety Recommendations on Material Flammability Standards
Background
Over the course of the Swissair Flight 111 (SR 111) investigation, the Transportation Safety Board of Canada (TSB) has looked beyond the specific circumstances of this particular accident to examine the full range of related factors that could compromise aviation safety.
On several previous occasions the TSB has issued safety advisories and recommendations focusing on specific safety deficiencies—products, procedures or practices that are, or have the potential to be, detrimental to flight safety.
The Board is issuing another series of safety recommendations, this time pertaining to aviation industry standards for the flammability of aircraft materials. While the Board acknowledges that there has been some progress in the development of materials for use in cabin areas, several other serious safety deficiencies have been identified.
The TSB has, therefore, issued three safety recommendations to prompt appropriate corrective action by the aviation industry and regulatory authorities.
Existing standards allow the use of flammable materials in the manufacture of certain aeronautical products. Because the most stringent fire tests today are reserved for seat cushions, cabin wall panels and other materials located in cabin areas, some of the most flammable materials in the pressurized portion of an aircraft tend to be located in hidden, remote or inaccessible areas. In these areas they have the potential to contribute to an uncontrollable in-flight fire.
Apart from sustaining or propagating fires, many flammable materials pose additional hazards, including heat release, smoke generation and the emission of toxins. For most materials, there are currently no regulatory restrictions regarding permissible levels of these combustion byproducts. The most effective means to mitigate these additional threats is to prevent the use of any material that sustains or propagates fire.
The TSB believes that no material, regardless of its location, type or quantity, should be allowed in the manufacture of an aircraft if it can sustain or propagate a fire in progress. Therefore, the Board recommends that:
For the pressurized portion of an aircraft, flammability standards for material used in the manufacture of any aeronautical product be revised, based on realistic ignition scenarios, to prevent the use of any material that sustains or propagates fire. (A01-02)
General Comment
Several airworthiness authorities, including Transport Canada (TC), the Federal Aviation Administration (FAA) and the European Joint Aviation Administration (JAA) are coordinating efforts on material flammability standards and have extensive programs and projects, underway or planned, related to the topics covered in these recommendations. The effectiveness of any action taken as a result of these efforts will depend upon a harmonized approach among the FAA, JAA and TC regarding their implementation. In a meeting October 5, 2001, TC, the FAA and the JAA confirmed their commitment to cooperate in the realization of the objectives of these recommendations.
Response A01-02
TC agrees with the need to revise, based on realistic ignition scenarios, the flammability standards for materials used in the manufacture of aeronautical products that are installed within the pressurized portion of an aircraft. TC is working in conjunction with the FAA and the JAA to promote a harmonized approach on this issue.
The FAA has advised TC that they concur with this recommendation and that the agency is developing new test requirements for materials in inaccessible areas of the aircraft in order to bring the level of flammability of all materials to that proposed for thermal acoustical insulation. These test requirements will include wiring, ducting, shielding and foam and the test methods will be refined through the International Aircraft Fire Test Working Group. The FAA is also pursuing test procedures and enabling technology for ultra fire resistant interior cabin materials.
As these improved flammability test standards and increased fire-resistant materials become available the certification standards and screening tests developed in conjunction with the other airworthiness authorities will be incorporated in Canadian regulatory standards.
Interim Aviation Safety Recommendations on Material Flammability Test Requirements for Aircraft Wiring
With some modern digital flight control systems relying totally on wire interconnections, the importance of electrical wires in aircraft is increasing. Indeed, large jets today may contain more than 250 kilometres of wire.
The insulating material on wires can become cracked, stretched, cut or chafed during normal aircraft operations. This exposes the metal conductor, which can short-circuit and produce an electrical arc. An arc, in turn, can produce high temperatures that can ignite a fire.
The failure of electrical wires can have disastrous consequences. A review of data shows that electrical systems have been a factor in about half of aircraft occurrences that involved smoke or fire, and that wiring has been implicated in about 10% of those occurrences. In the case of SR 111, 20 pieces of wire recovered from the wreckage showed signs of an electrical arcing event. No conclusions have yet been drawn regarding their role in the catastrophic fire.
Despite the potential hazards, failure tests for wires are not required by regulation. Under current certification standards, the only flammability performance criterion required to be measured for wire insulation material is the behaviour of a single unpowered wire when it is exposed to a flame.
Given the large quantity of wire in aircraft, its potential to fail, and its capacity to ignite fires, the Board is concerned by the absence of meaningful performance standards. Therefore, the TSB recommends that:
A certification test regime be mandated that evaluates aircraft electrical wire failure characteristics under realistic operating conditions and against specified performance criteria, with the goal of mitigating the risk of ignition. (A01-03)
Response A01-03
TC agrees that evaluation of aircraft wiring should be based on realistic operating conditions. The Canadian Airworthiness Manual 525.1357 specifies the protection required against aircraft wiring faults and 525.1351(b)(4) requires the electrical system to be tested to ensure that transients due to electrical faults will not create a fire hazard.
The FAA has advised TC that they concur with this recommendation and have initiated a project to revise the standards for wiring performance and test requirements. The FAA Wire Systems Harmonization Working Group will identify requirements for wire system safety and the assessment methodology will include common mode analysis, safety zonal analysis and specific risk analysis. The FAA is also evaluating the requirement for the installation of arc fault circuit breakers to reduce the chance of ignition from an electrical fault.
TC is also participating in a FAA Aging Transport Systems Rule Making Advisory Committee (ATSRAC) that has identified a wire system certification requirement as a task to be studied in cooperation with industry and other airworthiness authorities. TC will take action after ATSRAC recommendations are made and an approach is adopted by airworthiness authorities for current operating aircraft and future certification programs.
TC will continue to cooperate in these research activities associated with aircraft electrical wire failure characteristics and will introduce, in harmonization with other airworthiness authorities, the appropriate changes to certification test requirements and standards that are required.
System Evaluation: Fire Hardening Considerations
Modern aircraft contain numerous systems that serve various functions, such as air conditioning, oxygen supply, hydraulic and electrical power. Under existing certification standards, these systems must be designed and installed according to a "fail-safe" methodology. This means that, should a system fail, there are built-in mechanisms to ensure the aircraft can continue to be operated safely. Typically, however, the tests used to certify such systems do not assess the consequences of that system’s failure as a result of an in-flight fire.
Aircraft systems contain a variety of dissimilar materials, some of which will fail before others when exposed to fire. The resulting partial failure of some systems may aggravate a fire in progress. To address this concern, the Board believes that aircraft systems should be assessed for fire resistance. Consequently, the Board recommends that:
As a prerequisite to certification, all aircraft systems in the pressurized portion of an aircraft, including their sub-systems, components, and connections, be evaluated to ensure that those systems whose failure could exacerbate a fire in progress are designed to mitigate the risk of fire-induced failures. (A01-04)
Response A01-04
TC agrees that any system in the pressurized portion of an aircraft should be evaluated before being certified to ensure that the system cannot contribute to an ongoing in-flight fire. The Canadian Airworthiness Manual 525.869 specifies fire protection requirements for electrical, vacuum and oxygen systems and current certification practice requires evaluation of those systems where specific fire risks are likely to occur.
The United States Federal Aviation Regulation (FAR) 25.1309 requires that a system safety analysis be conducted as part of the certification process to ensure that equipment failures will not have any adverse effect on the safety of the aircraft. The FAA has directed that the Wire Systems Harmonization Working Group to recommend whether the methods of compliance with FAR 25.1309 should be mandated.
Extensive projects are underway by airworthiness authorities in conjunction with the industry to develop improved flammability standards to minimize the probability of materials propagating fire when subjected to realistic fire threats. The corrective actions being considered by the FAA for improved material standards, redesigned circuit breakers and more comprehensive wiring insulation tests all contribute to the intent of a systematic analysis called for in the recommendation.
TC will continue to cooperate with the FAA to clarify any additional amendments to the present certification standard that will promote a system that has been designed and installed using a fail-safe methodology. TC will review the applicable Canadian Aviation Regulations on system fire protection in conjunction with the results of the ongoing research projects and will harmonize any changes required with the other airworthiness authorities.
Should you require further information, please contact Aviation Safety Analysis at asi-rsa@tc.gc.ca