What happened
On a visual flight rules flight from Prince George to Princeton, British Columbia, a Cessna 210A, registration C-FNTH, experienced a sudden loss of engine power during its final approach to Runway 03. As the pilot transitioned to a left-hand downwind pattern, the aircraft was approximately three nautical miles from the aerodrome when the pilot reduced power to idle and extended the landing gear. At this moment, a smell of fuel became noticeable in the cabin.
Upon attempting to correct the descent by advancing the throttle, the engine failed to respond to the power increase. Before the pilot could activate the auxiliary fuel pumps, the aircraft's landing gear struck a stand of trees. The descent continued until the aircraft struck a large pine tree and an unoccupied house, coming to rest less than half a nautical mile from the runway. The pilot and one passenger sustained serious injuries.
The investigation
Investigators examined the aircraft's maintenance history and the fuel system components. Prior to the flight, the pilot, who also served as the aircraft's maintenance engineer, had performed an annual inspection. During this process, a leaking fuel unit had been repaired and reinstalled. Notably, there were no entries in the aircraft's technical or journey logs regarding this specific repair or the subsequent test flight, during which the pilot had also noted a fuel odor.
Detailed inspections of the fuel system revealed that while fuel was present at the fuel distributor, it was not found in the line between the engine fuel pump and the fuel unit. However, investigators determined this lack of fuel was likely due to damage sustained during the crash or during the transport of the wreckage. The fuel tanks were found to be breached during the impact, and the fuel quantity was deemed sufficient for the flight.
An engineering examination of the fuel selector valve revealed that an internal o-ring was deteriorated and contained debris, which prevented the valve from operating perfectly. However, this defect was not expected to cause an engine failure.
Findings
- The engine stopped for undetermined reasons.
- The pilot attempted to increase power on final approach, but the engine failed to respond.
- Fuel exhaustion, fuel starvation, or fuel tank venting issues were ruled out as causes.
- A deteriorated o-ring in the fuel selector valve allowed fuel to flow even when the valve was in the OFF position, though this was not a cause of the engine failure.