NTSB Identification: LAX91LA382.
The docket is stored on NTSB microfiche number 45498.
Accident occurred Tuesday, September 03, 1991 in REDWOOD CITY, CA
Probable Cause Approval Date: 05/03/1993
Aircraft: PIPER PA-28R-200, registration: N2080T
Injuries: 1 Serious.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

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 National Transportation Safety Board determines the probable cause(s) of this accident to be:

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.

Index for Sep1991 | Index of months