What happened
On 6 July 2002, a Mooney M20J, registration G-MUNI, was conducting a Licence Proficiency Check at Fairoaks, Surrey. The flight involved the aircraft owner, acting as the handling pilot, and an examiner serving as the legal commander. Following successful engine start and taxi procedures, the aircraft commenced its takeoff roll from Runway 24.
Shortly after liftoff, at an altitude of approximately 100 to 150 feet, the engine experienced a sudden and severe loss of power. There had been no prior indications of malfunction, such as rough running or misfiring. The commander immediately initiated emergency procedures, maintaining a safe airspeed and a glide attitude. To avoid a line of trees crossing the takeoff path, the commander directed the aircraft toward a suitable area in a field to the right of the runway centerline. The aircraft struck several fences before coming to a halt in an adjoining field. While the aircraft sustained substantial damage to the propeller, fuselage, and both wings, there were no injuries to the crew.
The investigation
Investigators examined the fuel system and the aircraft's recent history. The aircraft had been parked outdoors at Fairoaks for several months. On the day of the accident, the aircraft had been refueled, and the period preceding the flight had been characterized by very heavy rainfall.
Upon inspection of the fuel system, investigators found that both fuel tanks were full. When the fuel line between the engine-driven pump and the fuel injector was disconnected, a significant amount of water was drained from the system. Inspections of the fuel filler cap seals, seatings, and the locking mechanism spindle revealed no defects that would allow rainwater to enter the tanks.
Findings
- The engine failure was caused by water contamination in the fuel system.
- A large quantity of water was found in the fuel line between the engine-driven pump and the fuel injector.
- The aircraft had been exposed to heavy rainfall while parked in the open following a recent refueling.
- The gascolator drain, which is the lowest drain in the system, is difficult to check without assistance and can be easily overlooked due to its central location and the difficulty of collecting and settling the fluid to identify contaminants.