What happened
On 19 May 2011, a Pegasus Quantum 15, registration G-CCYL, was performing a private flight at Harringe Court Airfield in Kent. Following a successful takeoff, the pilot reached an altitude of approximately 500 ft agl. At this height, the pilot attempted to land on the remaining portion of the reciprocal runway. During this maneuver, the engine began running roughly and subsequently lost power.
While there was enough altitude to return to the airfield, the aircraft struck the ground heavily and came to a stop resting on its left wingtip. The pilot sustained no injuries, though the aircraft suffered damage to the wing and engine.
The investigation
Investigators examined the engine to determine the cause of the power loss. The inspection identified damage to the underside and crown of the rear piston, as well as damage to the bottom of the spark plugs located in the rear cylinder. The evidence indicated that foreign object debris had traveled from the crankcase, through the rear cylinder inlet valve, and into the cylinder.
Following the initial incident, the pilot replaced all spark plugs and attempted a second takeoff. While this second flight initially appeared normal, the engine began running roughly again at an altitude of 90 ft above the runway. No defects were found within the crankcase, and no additional foreign objects were identified. It remained unclear exactly when the debris had entered the crankcase.
Findings
- The engine failure was caused by foreign object debris passing from the crankcase into the rear cylinder.
- The debris caused physical damage to the rear piston and the spark plugs.
- The presence of the debris within the engine's internal components led to the loss of power during both the initial landing attempt and the subsequent takeoff attempt.