What happened
In the early morning hours of 23 January 2024, a British Aerospace P.L.C. Jetstream Model 3212, registered as C-FNAA, departed Fort Smith Airport (CYSM) in the Northwest Territories. The flight, operated by Northwestern Air Lease Ltd., was an instrument flight rules mission bound for Diavik Aerodrome (CDK2). On board were a captain, a first officer, and five passengers.
Shortly after taking off from Runway 30, the aircraft began a descent that led to a collision with trees approximately 0.5 nautical miles from the runway end. The aircraft then struck the terrain 0.6 nautical miles from the runway. The impact destroyed the aircraft and triggered a post-impact fire. The accident resulted in 5 fatalities (the captain, the first officer, and four passengers), while one passenger sustained minor injuries after being ejected from the wreckage.
The investigation
Investigators established that the captain had intentionally maintained a high airspeed and low pitch attitude during the initial climb to clear potential snow from the aircraft's surfaces. During the climb, the crew attempted to retract the landing gear. Due to extreme cold—with temperatures below −20 °C—and the high airspeed, one of the main landing gear units failed to retract fully.
In response to a call from the first officer to reduce speed, the captain decreased engine power to assist the gear retraction. This reduction in power caused the aircraft to enter an unplanned descent at 114 feet above the ground. The crew, focused on the landing gear indication and airspeed, did not realize the aircraft was losing altitude until the moment of impact.
Findings
- The primary cause of the accident was the inadvertent descent following a reduction in engine power intended to resolve a landing gear retraction issue.
- The crew's attention was diverted by the abnormal landing gear indication and airspeed management, preventing them from noticing the loss of altitude.
- A known issue regarding the main landing gear's failure to lock in the retracted position had not been documented in the aircraft's journey log.
- The company had developed an informal, undocumented workaround for the gear issue, which had become a normalized practice among pilots.
- The roles and responsibilities for the pilot flying and the pilot monitoring were not explicitly defined in the operator's manuals for the departure phase.
- The crew did not utilize the manufacturer's abnormal checklist following the gear malfunction.
Safety action
In October 2024, Northwestern Air Lease Ltd. updated its standard operating procedures manual for the Jetstream 3100 and 3200 series to provide clearer instructions on managing abnormal and emergency flight situations.