What happened
On the morning of December 22, 2012, Perimeter Aviation Flight 993 was delayed for approximately four hours at Winnipeg, Manitoba, due to various issues, including necessary repairs to the aircraft's cargo door. Once the flight departed for Sanikiluaq, Nunavut, the crew identified that they lacked essential published information regarding the approach and landing procedures for their destination. To avoid returning to Winnipeg, the captain contacted the company via radio to acquire the necessary data.
The crew initially intended to perform a straight-in visual approach to land eastbound on Runway 09. However, prevailing weather conditions prevented this plan. Because no instrument approach procedure existed for Runway 09, the crew utilized the published procedure for Runway 27 and attempted a visual circling maneuver to land into the wind on Runway 09. This attempt failed due to insufficient visibility, and a subsequent circling attempt also resulted in the crew losing sight of the runway.
During the flight, updates indicated that the crew's alternate destination, Kuujjuarapik, was no longer a viable option. Despite the challenges, the crew continued attempting to land at Sanikiluaq. During these repeated attempts, the crew experienced heightened levels of stress, fatigue, and frustration, which led to a breakdown in communication and narrowed their attention. On a final attempt to land westbound on Runway 27, a tailwind increased the aircraft's groundspeed. This caused the aircraft to approach the runway at an excessive height, speed, and descent angle. The captain attempted to reject the landing, but the aircraft struck the ground before the maneuver could be completed.
The investigation
The investigation focused on the sequence of events leading to the approach-and-landing accident, specifically examining the impact of the initial flight delays, the lack of published approach information, and the deteriorating weather conditions. The TSB analyzed the crew's decision-making process and the physiological and psychological factors affecting the flight crew during the repeated landing attempts.
Findings
- The crew faced significant pressure to land, which contributed to increased workload, frustration, and fatigue.
- These stressors resulted in attentional narrowing and a breakdown in crew communication.
- The use of a tailwind during the final approach to Runway 27 led to an unstable approach characterized by excessive speed, height, and descent rate.