What happened
On 19 June 1998, a Lancair 320, registration G-BTOR, was conducting a private flight from Biggin Hill. The aircraft had been refuelled for a 50-minute return journey and was cruising at 2,000 feet with a fuel flow of 9.2 US gallons per hour. While flying south of Andover and communicating with Farnborough Radar to rejoin the Thruxton circuit, the engine experienced a misfire and the power dropped to idle.
The pilot attempted to rectify the issue by moving the mixture to rich and activating both the transfer and electric booster pumps. Despite exercising the throttle, the engine failed to regain power and continued to run at idle or windmill speed. At approximately 1,400 feet, the pilot identified a potential landing field and lowered the landing gear. However, upon realizing the field was covered in barley, the pilot attempted to retract the gear. During this maneuver, the left wing struck the crop while the aircraft was likely in a stalled attitude. This impact caused the aircraft to swing nose-down and subsequently break up. Both occupants sustained minor injuries and escaped the wreckage.
The investigation
Investigators examined the wreckage and the engine components following the accident. While fuel was found to be present up to the injector, the outgoing lines were dry. A detailed strip of the engine and testing of the injector pump were conducted, but these procedures failed to identify a definitive mechanical cause for the power loss.
Findings
- The engine power loss occurred during the cruise phase of the flight, leading to a loss of altitude.
- The aircraft struck a barley field while the landing gear was in a partially retracted position.
- Vapour lock in a recently lagged fuel line located against the crankcase was considered a possible cause of the engine failure.