Air Transportation Safety Recommendation A18-02, A18-03

The Honourable Marc Garneau, P.C., M.P.
Minister of Transport
Transport Canada
Place de Ville, Tower C-29
330 Sparks Street
Ottawa, Ontario
K1A 0N5

14 December 2018

Dear Minister,

Background

On 13 December 2017, an Avions de Transport Régional ATR 42-320 aircraft (registration C-GWEA, serial number 240), operated by West Wind Aviation LP (West Wind) as flight 282 (WEW282), conducted an instrument flight rules flight from Prince Albert (Glass Field) Airport (CYPA), Saskatchewan, to Fond‑du-Lac Airport (CZFD), Saskatchewan. During the descent, the aircraft encountered icing conditions and the crew activated the anti-icing and de-icing systems. When the de-icing and anti-icing systems were turned off 9 minutes later, while the aircraft was on final approach, residual ice remained on portions of the aircraft.

After landing, WEW282 exited the runway and shut down on the ramp at CZFD, at 1727 Central Standard Time. Some passengers disembarked and some cargo and baggage were removed from the aircraft; other passengers boarded and outbound cargo and baggage were loaded onto the aircraft. After the passengers had boarded, 1 pilot conducted a pre-flight inspection of the aircraft and subsequently advised the other pilot that the aircraft had ice on it. West Wind had some de-icing equipment in the terminal building at CZFD; however, the aircraft was not de-iced^{Footnote 1} before takeoff.

At 1812:03, the takeoff was initiated with ice contamination on the aircraft.

At 1812:30, WEW282 lifted off from Runway 28, bound for Stony Rapids Airport (CYSF), Saskatchewan, with 3 crew members (2 pilots and 1 flight attendant) and 22 passengers on board.

At 1812:47, the aircraft collided with trees and terrain approximately 1400 feet west of the departure end of Runway 28.

Nine passengers and 1 crew member received serious injuries, and the remaining 13 passengers and 2 crew members received minor injuries. One of the passengers who had received serious injuries died 12 days after the accident. The aircraft was destroyed.

As a part of its ongoing investigation into this occurrence (A17C0146), the TSB has identified a key safety issue that must be addressed to improve the safety of air transportation in Canada, namely aircraft taking off from remote northern airports with frost, ice, or snow adhering to critical surfaces.^{Footnote 2}

Aircraft taking off with frost, ice, or snow adhering to any critical surface

Adverse consequences

Conducting a takeoff with contaminants adhering to aircraft critical surfaces will result in aerodynamic degradation, which can lead to difficulty controlling the aircraft or to a loss of control and collision with terrain.

Defence analysis

A major component of a safe transportation system is the set of defences put in place to protect people, property, and/or the environment. These defences can be used to

• reduce the probability of unwanted events; and
• reduce the negative consequences associated with unwanted events.

The regulatory provision underpinning the defences against takeoff in contaminated aircraft is Canadian Aviation Regulations (CARs) subsection 602.11(2), which states, “No person shall conduct or attempt to conduct a take-off in an aircraft that has frost, ice or snow adhering to any of its critical surfaces.”^{Footnote 3}

To assist aviation personnel in complying with this provision, there is an administrative framework of

• Transport Canada regulations and standards;
• flight crew operating manuals and airplane flight manuals produced by aircraft manufacturers;
• programs, policies, and procedures established by air operators; and
• training provided to pilots and ground staff.

However, this framework can be ineffective without sufficient oversight at the regulatory and operational levels, and/or with operating conditions such as

• active ground icing conditions;
• absent, inaccessible (Figure 1), or inadequate inspection or de‑ice/anti-ice equipment;
• very short holdover times^{Footnote 4} for Type I de-icing fluids^{Footnote 5}; or
• an absence of anti-icing^{Footnote 6} capability.

In this occurrence, one of the operating conditions was the equipment available to the pilots of WEW282 at CZFD. Neither of the available ladders (Figure 2 and Figure 3) was high enough to permit an inspection or de-icing of the ATR 42 wing or horizontal stabilizer.^{Footnote 7}The West Wind de-icing equipment (Figure 4) was a hand-held spray system with a small-capacity heated fluid reservoir, and a 20 L container of additional Type I fluid. Another air operator also had a small, heated hand-held spray system (Figure 5) in the terminal building. These systems, even if combined, had insufficient fluid capacity to de‑ice an ATR 42.

No anti-icing equipment was available at CZFD. None of the available ladders or de-icing equipment were used by the crew of WEW282.

Compliance with the administrative framework would have prevented WEW282 from taking off with contaminants on its critical surfaces. However, some of the organizational defences in place, such as equipment, were inadequate. Moreover, taking off with contaminants on the aircraft breached a number of otherwise adequate administrative defences, such as prohibitions in the ATR 42 Flight Crew Operating Manual, the company's operations manual, and the company's ATR 42 standard operating procedures.

Assessment of the risk

To assess the systemic risk posed by the circumstances present in this occurrence, in July and August 2018, the TSB sent a questionnaire to commercial pilots currently employed by air operators in Canada operating at remote northern airports under Part VI or Part VII of the CARs.

The TSB distributed pilot questionnaire invitations to 83 Canadian commercial air operators that, on 31 May 2018, operated under subparts 604, 702, 703, 704, and 705 of the CARs.^{Footnote 8} The selected operators were those likely to have flights taking off from the airports in Figure 6, below. The questionnaire deliberately excluded large national airline operators that operate primarily from airports in southern Canada.

Invitations were also sent to several pilot unions representing pilots employed by the selected operators, and to an aviation industry association of air operators.

All organizations that received the invitation had access to the questionnaire questions, and were able to choose whether to forward the invitation to their pilots. Questionnaire participation was both voluntary and anonymous; the questionnaire did not request location information or operator identities.

The selected air operators that provided staffing information employed 2768 pilots. Air operators that did not provide pilot numbers are estimated to employ an additional 500 pilots. It is not known how many pilots received invitations forwarded by their operator or union.

Completed questionnaire responses were received from 655 pilots. Preliminary analysis of questionnaire responses indicates that, at remote northern airports in Canada, aircraft operating under CARs Part VI or Part VII frequently take off with contaminated critical surfaces. Some respondents reported negative consequences, such as degraded takeoff and climb performance or difficulty controlling the aircraft.

Respondents reported seeing, within the past 5 years, transport category jets and turboprops, commuter turboprops, and all types of air taxi aircraft take off with contaminants adhering to the critical surfaces.

Questionnaire respondents were not asked to indicate where they had seen contaminated aircraft take off; however, some did so, indicating a wide geographic distribution of events across Canada. Some respondents reported seeing events regularly at some remote northern airports.

Many questionnaire respondents answered that they rarely have access to adequate inspection equipment and de-icing equipment (Appendix A). The unavailability of adequate equipment is a significant underlying factor that prevents pilots from being able to conduct a proper pre-flight inspection for contaminants and from de-icing an aircraft that is contaminated. Only 37% of respondents reported that they are able to have their aircraft de-iced effectively at remote airports.

Most questionnaire respondents answered that they rarely have access to adequate anti‑icing equipment. Only 15% of respondents reported that they are able to have their aircraft anti-iced effectively at remote northern airports. Where anti-icing is not available, flights operating in active ground icing conditions can experience Type I fluid failure^{Footnote 9} because of its short holdover time.

As demonstrated by this occurrence, losses of control and collisions with terrain can result in destruction of the aircraft and death. Similar occurrences investigated by the TSB and other agencies over the past 36 years (appendices B and C) indicate that this catastrophic consequence still occurs occasionally. Canada is substantially exposed to the risk of accident recurrence, with a large and diverse fleet of aircraft operating at remote northern airports when icing conditions are present.

The combined probability and severity of this safety deficiency pose a high risk to transportation safety.

Identification of high-risk locations for immediate mitigation

The duration of cold weather and icing conditions varies widely across Canada. Many remote northern airports have an icing season of 10 months or more. Icing conditions can be both severe and persistent.

Thousands of flights take off every year from remote northern airports. Some airports serve as hubs, experience higher traffic volumes, and may have better equipment.

The risks of adverse consequences likely vary from airport to airport. Identifying high-risk locations for immediate mitigation has the potential to quickly reduce the likelihood of aircraft taking off with frost, ice, or snow adhering to any critical surface at those locations.

Transport Canada, air operators, and airport authorities have the capacity to identify high-risk locations, analyze them for hazards and risks, and take mitigating action.

Therefore, the Board recommends that

Improving compliance

TSB pilot questionnaire responses indicate that the absence of adequate equipment increases the likelihood that pilots will conduct a takeoff in an aircraft that has frost, ice, or snow adhering to any of its critical surfaces. Additionally, the responses indicate that, in the absence of adverse consequences, taking off with contamination on critical surfaces is a deviation that has become normalized. Therefore, providing adequate de-icing and anti-icing equipment may not be sufficient to reduce the likelihood of aircraft taking off with contaminated critical surfaces.

This occurrence and the pilot questionnaire responses indicate that some of the current defences used by the Canadian air transportation system to prevent aircraft from taking off with frost, ice, or snow adhering to any critical surface are less than adequate.

TSB questionnaire responses show that takeoffs with contaminated critical surfaces occur in substantial numbers across the spectrum of aircraft and operating categories at remote northern airports.

Non-compliance with CARs subsection 602.11(2), flight crew operating manuals, company operations manuals, and company standard operating procedures can be a single point of failure of defence framework. To mitigate this, Transport Canada and air operators must take urgent action to ensure better compliance.

Organizations can audit equipment (to inspect, de-ice, and anti-ice aircraft), policies (such as ground icing operations programs and contingencies for situations where resources are not available), training (for pilots and ground staff), and operations (procedures, compliance, deviations). Air operators could incorporate questions in before-start and before-takeoff checklists with a requirement for a clean aircraft or a mitigation response from the pilot-in-command.

Accidents related to contaminated aircraft will continue to occur until the industry and the regulator approach the issue as systemic and take action to eliminate underlying factors that can negatively affect pilot compliance.

Therefore, the Board recommends that

Next steps

At this time, the TSB investigation into this accident is ongoing and the investigation team is completing its analysis of the information collected. The investigation will then move into the report phase and a draft report will be prepared and sent out for review and submission of representations by the designated reviewers, per our standard practice. As the investigation proceeds, should the TSB identify any additional safety deficiencies in need of urgent attention, the Board may make further recommendations or issue other safety communications.

In accordance with subsection 24(6) of the Canadian Transportation Accident Investigation and Safety Board Act, we hereby ask that you advise the Board in writing within the next ninety days of any action taken or proposed to be taken in response to the two enclosed recommendations.

Yours sincerely,

Enclosures: Appendices A, B, and C

Appendices

Appendix A – Pilot questionnaire responses (n = 655)

Appendix B – Similar occurrences in Canada

Appendix C – Similar occurrences outside Canada