Pegasus Quantum 15, G-CCYL
After an uneventful takeoff, at approximately 500 ft agl, the engine began to run roughly and lost power. There was sufficient altitude available for the pilot to return to the airfield where he carried out a landing on the reciprocal runway. An inspection of the engine revealed damage to the bottom of the spark plugs fitted in the rear cylinder. After replacing all of the spark plugs the engine ran smoothly and the pilot, believing the fault had been corrected, prepared to takeoff again. No problems were observed during the second takeoff, but at a height of 90 ft above the runway, the engine began to run roughly once again. With insufficient height to land in the next field, the pilot attempted to land on the remaining length of the runway. The aircraft landed hard and came to a halt resting on its left wingtip. The pilot was uninjured. A detailed examination of the engine revealed damage to the crown and underside of the rear piston. The evidence suggested that this had been caused by foreign object debris, passing from the crankcase, through the rear cylinder inlet valve, into the cylinder. No defects were observed within the crankcase and no further foreign objects were found. It could not be determined when the foreign object debris had entered the crankcase.
Pegasus Quantum 15, G-CCYL 08-11.pdf (223.22 kb)