What happened
On 13 December 2017, an ATR 42-320, registration C-and-GWEA, was performing a series of scheduled flights across northern Saskatchewan for West Wind Aviation L.P. The flight began in Saskatoon and included a stop at Prince Albert. During the approach to Fond-du-Lac Airport, the aircraft encountered in-flight icing. While the crew utilized the aircraft's de-icing and anti-icing systems, residual ice remained on certain surfaces. Upon landing at Fond-du-Lac, the aircraft remained on the ground for approximately 48 minutes. During this period, despite the absence of active precipitation, environmental conditions allowed for additional frost and ice to accumulate on the airframe.
Prior to the next leg of the journey to Stony Rapids, the first officer performed a visual inspection of the aircraft. Due to poor lighting and inadequate inspection tools, the full extent of the ice accumulation was not identified, though the crew was aware of some ice presence. The decision was made to proceed with the departure without de-icing the aircraft. During the takeoff roll on Runway 28, the aircraft's performance was significantly compromised by the ice, which had increased drag by 58% and decreased lift by 25%. Shortly after becoming airborne, the aircraft experienced an uncommanded left roll caused by asymmetric lift. The crew attempted to correct the roll, but the aircraft entered an intensifying oscillation. This loss of control led to the aircraft striking the terrain 17 seconds after takeoff.
Findings
- The aircraft's structural design lacked sufficient energy absorption, leading to a collapse of the wing into the cabin upon impact.
- The crew's decision to depart was influenced by continuation bias and a normalized practice of departing remote airports without de-icing due to lack of available services.
- The accident resulted in 1 fatality and 9 serious injuries, with 13 passengers and 2 crew members sustaining minor injuries.