What happened
At approximately 1815 mountain daylight time, a Pitts Special aerobatic aeroplane departed from Runway 33 at Invermere, British Columbia, for a recreational flight. The pilot occupied the rear seat while a passenger sat in the front. During the initial climb, the aircraft was observed performing a right turn followed by a steep, descending left turn that reached an angle of approximately 120 degrees from the departure heading. The aircraft's nose was pointed toward the ground, though it appeared to lift slightly just before the impact. The aeroplane struck the ground in a field roughly 650 feet from the runway end, flipped over, and came to rest on its back. The pilot sustained fatal injuries, while the passenger suffered serious, life-threatening injuries. There was no fire at the scene.
The investigation
Investigators examined the wreckage and the aircraft's fuel systems to determine the cause of the power loss. While the engine showed no mechanical malfunctions that would prevent power production, investigators found that the fuel injectors and lines from the fuel distributor were empty of fuel. Analysis of the fuel system revealed that the auxiliary tank contained green (100) grade fuel, which contained water and particulate matter. In contrast, the main tank contained blue (100LL) fuel. Although the valve connecting the auxiliary tank to the main tank was closed, contaminated fuel was identified in the line between the distributor and the engine baffle.
Examination of the propeller and engine instruments indicated that the engine was not delivering full power at the moment of impact. The investigation also noted that the aircraft had experienced a similar engine power loss event three weeks prior, which was attributed to water in the fuel system.
Findings
- The engine lost power due to contaminated green (100) fuel found within the aircraft's fuel lines.
- The pilot was likely attempting to return to the Invermere aerodrome following the power loss.
- Due to the aircraft's proximity to the runway and the lack of engine power, the pilot was unable to stop the steep descent before the aircraft struck the ground.