News release

In its investigation report (A17C0146) released today, the Transportation Safety Board of Canada (TSB) determined that the lack of adequate de-icing equipment and the practice of taking off without de-icing led to the fatal December 2017 accident involving a West Wind Aviation ATR-42 aircraft on the territory of the Fond Du Lac Denesųłiné First Nation in Saskatchewan.

On 13 December 2017, an ATR 42-320 aircraft, operated by West Wind Aviation as flight WEW282, departed Fond-du-Lac Airport, Saskatchewan, for Stony Rapids, Saskatchewan. Shortly after takeoff, the aircraft collided with trees and terrain about 450 m west of the departure end of Runway 28. The aircraft was destroyed. All 22 passengers and three crew members on board were injured, ten of them seriously. One passenger died days later.

Early in the investigation, it was determined that the aircraft took off from Fond-du-Lac Airport with ice contamination on the aircraft’s critical surfaces. The operator had some de-icing equipment available in the terminal building, but it was not adequate for de-icing an ATR 42. In 2018, the TSB issued two recommendations following the occurrence. The first was aimed at making sure adequate de-icing and anti-icing equipment is available for those operators who need it (A18-02). The second urged Transport Canada (TC) to take action to improve compliance with the regulations to reduce the likelihood that crews take off with snow or ice contamination (A18-03).

“Although Transport Canada has said it agrees with the recommendations, and some steps have been taken, more action is required”, said Kathy Fox, Chair of the TSB. “Companies need to make more and better de-icing and anti-icing equipment available. TC must also increase the frequency of its targeted inspections. Until the TSB’s recommendations are fully implemented, what happened to this flight could still happen to other flights operating in Canada’s remote and northern airports.”

The investigation found that, well before the accident, during the descent toward Fond-du-Lac, the aircraft encountered icing conditions. The flight crew activated both the anti-icing and de-icing systems, but some ice remained on the aircraft. However, the crew did not notice any handling abnormalities and landed without incident. During the 45 minutes on the ground prior to the accident flight, icing conditions continued to be present, and additional ice formed on the aircraft. After carrying out a pre-flight inspection, the first officer notified the captain of the presence of some ice on critical surfaces, but there was no further discussion or action taken. Because the available inspection equipment was inadequate, the first officer’s ice inspection consisted of walking around the aircraft, at night, on a dimly lit apron, without a flashlight, and looking at the left wing from the top of the stairs at the left rear entry door. As a result, the full extent of the residual ice and ongoing accretion was unknown to the flight crew.

Departing from remote airports, such as Fond-du-Lac, with some amount of surface contamination on the aircraft’s critical surfaces, had become common practice, in part due to the inadequacy of de-icing equipment or services at these locations. The past success of these adaptations resulted in the unsafe practice becoming normalized and this normalization influenced the flight crew’s decision to depart.

During takeoff, the aircraft initially climbed; however, immediately after liftoff, the aircraft began to roll to the left without any pilot input. This roll was as a result of asymmetric lift distribution due to uneven ice contamination on the aircraft. This loss of control in the roll axis, which corresponds with the known risks associated with taking off with ice contamination, ultimately led to the aircraft colliding with terrain.

Following the impact with the ground, the survivable space between the floor above the main landing gear and the collapsed upper fuselage and structure was reduced. This led to severe injuries to the passengers seated in this area, including the subsequent death of one passenger. The design standards in effect at the time the ATR 42 was certified did not specify minimum loads the structure must be able to tolerate to allow a survivable space or minimum loads for fuselage impact energy absorption. As a result, the ATR 42 was not designed with these crashworthiness principles in mind.

This investigation also revealed a number of instances in which TC’s surveillance policies and procedures were inconsistently applied to the oversight of West Wind Aviation. For instance, between 2010 and 2013, TC had identified several concerns with West Wind’s Safety Management System (SMS). Despite this, TC decreased its surveillance of the company to a detailed inspection only every four years. When a detailed inspection did take place in 2016, it found “systemic failures” with the company’s SMS. Rather than issuing a Notice of Suspension, TC selected Enhanced Monitoring, a more moderate course of corrective action. If the application of Transport Canada’s surveillance policies and procedures is inconsistent, there is a risk that resulting oversight will not ensure that operators are able to effectively manage the safety of their operations.

Following the occurrence, West Wind has taken steps to improve its internal risk assessments, and now provides additional training, guidance, and better de-icing equipment to its crews.

See the investigation page and watch the explanatory video for more information.