What happened
On 1 August 2003, a Lake LA-4-200 Amphibian, registration G-SKID, was performing a private flight near Hawarden Airport when it experienced a loss of engine power shortly after takeoff. The aircraft, operated by a private owner, was carrying one pilot and one passenger.
During the initial climb, the pilot reported a hydraulic issue and attempted to use the emergency hand pump to raise the landing gear. As the aircraft continued its flight, witnesses observed the engine sounding rough and backfiring. While attempting a forced landing in a nearby field, the aircraft struck overhead power lines. The impact caused the aircraft to pitch violently nose-down and land inverted in a cornfield. The pilot sustained serious injuries, while the passenger escaped with minor injuries.
The investigation
The AAIB investigation focused on the engine' and fuel system performance. Examination of the wreckage revealed that the aircraft had struck small power lines, which severed two cables. The investigation also looked into the maintenance history of the aircraft, noting that it had been used infrequently, with only eight hours of flight time recorded between September 2000 and June 2002.
Technical analysis of the fuel system uncovered significant corrosion within the fuel filter element and the mechanical fuel pump. A sample of fuel taken from the fuel filter contained brown-colored water. Furthermore, the electric boost pump was found to have seized due to corrosion. While the pilot had reported a hydraulic issue during the flight, investigators determined this was not the primary cause of the accident.
Findings
- The engine failed to produce adequate power due to water contamination of the fuel system.
- This contamination was caused by the accumulation of moisture from condensation within the fuel tank, a common occurrence in aircraft that are parked for long periods.
- Extensive corrosion was present in the fuel filter, the mechanical fuel pump, and the electric boost pump, indicating that water had been present in the system for a significant duration.
- The required 50-hour maintenance check, which was due in April 2003, had not been performed; had this check been completed, the corrosion and water presence might have been detected.