What happened
On a daylight flight from Winnipeg to Norway House, Manitoba, a Swearingen SA226-TC, registered as C-FTNV, was completing its landing on Runway 05. The aircraft, operated by Perimeter Aviation Ltd., was carrying two crew members and seven passengers.
After touching down, the crew selected propeller reverse thrust. Immediately following this action, the aircraft began to veer toward the left. Despite attempts by the crew to regain directional control, the aircraft departed the runway surface, entered a patch of loose snow, and crossed a shallow ditch. The aircraft then climbed a rocky embankment, causing all three landing gear assemblies to collapse. The aircraft came to rest on its belly approximately 1,800 feet from the runway threshold. There were no injuries reported among the nine people on board.
The investigation
The investigation focused on the mechanical state of the engines and the sequence of pilot inputs. Investigators examined the aircraft's Beta system, which manages propeller pitch during ground operations. Analysis of the wreckage revealed that the left engine's fuel control support assembly had failed due to fatigue, causing a bolt to release and displacing the fuel control unit. This failure altered the propeller control dimensions, meaning the left engine reached the required Beta pressure for reverse thrust before the right engine did.
Examination of the runway surface showed continuous and uniform tire marks, indicating that the nosewheel steering and brakes were not being used at the moment the aircraft veered. The tracks suggested the deviation was caused by asymmetric thrust resulting from the uneven application of reverse power.
Findings
- The primary cause of the deviation was the pilot selecting thrust reverse before confirming that the Beta lights for both engines were illuminated.
- A fatigue failure in the left engine fuel control support assembly caused the left propeller to enter reverse thrust mode before the right propeller.
- This mechanical failure created a momentary period of asymmetric thrust that pulled the aircraft off the runway heading.
- While weather and runway conditions were appropriate for landing, the presence of accumulated snow near the runway edge contributed to the aircraft's path after it left the pavement.