What happened
On 4 March 2023, a Zenair CH 750, registration G-WXYZ, was conducting a private flight from Tatenhill Airfield toward Thruxton Airport. Approximately 30 minutes after departure, the pilot observed a red warning light appear on the instrument panel. While the specific nature of the warning could not be identified by the pilot, the engine subsequently ceased operation.
Recognizing the limited glide capabilities of the aircraft, the pilot attempted an immediate forced landing in a nearby field. During the maneuver, the aircraft struck a hedgerow and overturned, eventually coming to rest upside down on a road adjacent to the field. The pilot sustained minor injuries and was able to exit the wreckage without assistance after securing the fuel and electrical systems.
The investigation
Following the accident, the UK distributor for Zenair examined the wreckage to determine the cause of the engine failure. The investigation established that both fuel pumps were functional and the engine control unit (ECU) showed no operational anomalies. The distributor noted that the ECU features two redundant control lanes, making a single ECU fault an unlikely cause for engine stoppage. Additionally, while the battery could not be tested, the investigation found that low battery voltage was not a probable cause for the engine failure, as the ECU is powered by an engine-driven generator with a backup system.
Findings
- The engine failure was likely caused by fuel starvation or a blockage in the fuel flow.
- The aircraft was equipped with wing root fuel valves; if these had been closed, the engine's fuel header tank would have been depleted, triggering a low fuel warning.