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TSB Canada: better de-icing equipment and practices in remote and northern airports needed
29 October 2021

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 in Canada, according to the TSB investigation report (A17C0146).

On 13 December 2017, the ATR 42-320 aircraft departed Fond-du-Lac Airport, Saskatchewan, Canada. Shortly after takeoff, the aircraft collided with trees and terrain. The aircraft was destroyed. All 22 passengers and three crew members on board were injured, ten of them seriously. One passenger died days later.

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.

This investigation also revealed a number of instances in which Transport Canada’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.