What happened
On 9 August 2003, a Pioneer 300, registration I-6173, was engaged in a private flight near Raglan, Gwent. Following the completion of pre-flight inspections and engine power checks, the aircraft departed from a grass strip. After the takeoff was successful and the landing gear and flaps had been retracted, the engine ceased operation at an altitude of approximately 180 feet.
The pilot initiated a forced landing straight ahead into a field located near the Horse & Jockey Pub. While the aircraft successfully avoided straw bales within the harvested field, the impact caused damage to the propeller and the underside of the fuselage. Both the pilot and the passenger escaped the aircraft without injury.
The investigation
Investigators examined the circumstances leading to the engine failure, specifically focusing on the fuel used for the flight. Prior to departure, the aircraft had been refuelled with 15 litres of unleaded motor fuel, which had been stored in a metal container inside a hangar.
Analysis of the fuel's properties and the environmental conditions at the time of the accident was conducted. The investigation noted that the ambient air temperature was approximately 32°C. The pilot suggested that the engine stoppage was caused by fuel starvation.
Findings
- The engine failure was likely caused by vapour lock within the fuel system.
- The use of unleaded motor fuel, which is more volatile than standard AVGAS, contributed to the risk.
- High ambient temperatures (32°C) and the potential for the fuel to have been heated while stored in a metal container likely facilitated the formation of vapour in the fuel lines.