What happened
On 15 April 2012, a Yates JS MW6 (Modified) Merlin, registration G-MVSO, was conducting a check flight at Otherton Airfield in Staffordshire. The flight was being performed to revalidate the aircraft's Permit to Fly following a period of several years in storage. The pilot had already completed several runway maneuvers, including "bunny hops," and a twenty-five minute flight before attempting a subsequent takeoff.
While the aircraft was climbing through 700 ft, the engine suddenly lost power. The pilot was forced to perform an emergency landing in a field located just short of the Runway 34 threshold. Although there were no injuries to the pilot or the passenger, the aircraft sustained damage to the front forks and the nosewheel.
The investigation
Following the incident, the AAIB examined the aircraft's engine and fuel system. The investigation focused on the cause of the power loss during the climb. Investigators found that a fuel strainer, which is typically secured to the outlet at the base of the fuel tank, had become loose inside the tank. Additionally, this strainer was found to be obstructed by a thick, tar-like substance.
Findings
- The engine failure was caused by fuel starvation.
- The fuel strainer had become detached from its position at the bottom of the tank.
- The strainer was clogged with a tar-like residue, which prevented the flow of fuel.
- It was noted that the aircraft had been stored for several years with fuel remaining in the fibreglass tank, a condition that may have caused the tank material to degrade and contributed to the blockage.