What happened
On 13 June 2003, a Denney Kitfox Mk 4, registration G-BZIB, was conducting a series of test flights necessary for obtaining a Permit to Fly. During the flight, approximately 15 minutes after takeoff, the engine ceased operation while the aircraft was at 1,500 feet QFE near Leicester Airport.
Upon the loss of power, the pilot identified a suitable field containing a standing cereal crop for an emergency landing. To prioritize aircraft control, the pilot did not attempt an engine restart or communicate via radio. As the aircraft descended into the crop, which was approximately two and a half feet high, the speed decreased and the aircraft began to sink. The main wheels made contact with the crop, causing the aircraft to pitch forward and eventually come to rest in an inverted position after traveling roughly 30 to 40 feet.
Despite the impact, the two occupants remained uninjured. The crew members were able to exit through the doors, which had opened during the sequence. No fire occurred at the scene.
The investigation
Investigators examined the engine and fuel system to determine the cause of the power loss. The investigation established that the engine failure was caused by fuel starvation.
Detailed inspection of the fuel system revealed that debris had entered the fuel pipe and fuel pump. This debris was identified as a rubber jointing compound used during the aircraft's construction to seal the connections between rubber fuel pipes and metal hose nipples. It was noted that a previous ground run had experienced a similar blockage due to this substance, and although the pilot had advised the owners to clear the blockage, the underlying issue remained.
Findings
- The engine failure resulted from fuel starvation caused by debris in the fuel system.
- The debris consisted of rubber jointing compound used at the interface of rubber pipes and metal nipples.
- The use of such a compound in an aircraft fuel system is not considered standard engineering practice.
Safety action
- The Popular Flying Association is advised to issue a technical instruction providing guidance on the suitability of rubber jointing compounds and suggesting alternative methods for creating fuel-tight joints in aircraft fuel systems.