REDWOOD CITY, CA, USA
N2080T
PIPER PA-28R-200
THE 400 HOUR SINCE FACTORY REMANUFACTURED ENGINE BEGAN TO RUN ROUGH, THEN IT QUIT WITH A LOUD 'BANG.' THE PILOT WAS ATTEMPTING TO COMPLETE A FORCED LANDING IN A PASTURE AREA WHEN THE AIRCRAFT COLLIDED WITH THE GROUND. DISASSEMBLY OF THE ENGINE REVEALED THAT THE NUMBER TWO CYLINDER CONNECTING ROD AND ITS ASSOCIATED ROD CAP HAD FAILED. METALLURGICAL EXAMINATION OF ALL CONNECTING RODS AND CAPS WAS PERFORMED. THE #2 ROD AND CAP FAILED DUE TO A FATIGUE FRACTURE WITH AN ORIGIN ON THE BORE SURFACE. AREAS OF GALLING WERE FOUND ON BOTH THE ROD CAP AND THE CONNECTING ROD BORE. CRACKS WERE IDENTIFIED WITHIN THE GALLED AREA ON THE NUMBER TWO CONNECTING ROD BORE. EXAMINATION OF THE THREE REMAINING CONNECTING RODS AND THEIR CAPS REVEALED GALLED AREAS WITHIN THE BORES. THE METALLURGISTS STATED THAT HE HAD OBSERVED SIMILAR FAILURES ON HELICOPTER PISTON ENGINES WHICH WERE KNOWN TO HAVE HAD AN OVERSPEED.
THE FATIGUE FAILURE OF THE NUMBER TWO CONNECTING ROD AND ROD CAP DUE TO AN ENGINE OVERSPEED CONDITION WHICH THE RODS AND ROD CAPS WERE EXPOSED AT SOME UNDETERMINED HISTORICAL POINT.
Source: NTSB Aviation Accident Database
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