NTSB Identification: LAX88LA122.
The docket is stored on NTSB microfiche number 38130.
Accident occurred Thursday, March 10, 1988 in LOWER LAKE, CA
Probable Cause Approval Date: 12/29/1989
Aircraft: PIPER PA-34-200T, registration: N1555X
Injuries: 1 Uninjured.

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

DRG THE LNDG ROLL, THE LEFT MAIN LNDG GEAR COLLAPSED & THE ACFT VEERED OFF THE RWY, FURTHER DAMAGING THE AIRCRAFT. AN INVESTIGATION REVEALED THE LEFT MAIN LANDING GEAR TRUNNION HAD FAILED. IT HAD FAILED DIAGONALLY APRX 5 INCHES FROM THE BOTTOM OF THE TRUNNION & 2 INCHES BELOW THE ROTATING AXIS. A METALLURGICAL EXAM REVEALED PREEXISTING FATIGUE WHERE THE FRACTURE OCCURRED. THE TRUNNION HAD BEEN IN SVC FOR APRX 4081 HRS OF OPERATION. PIPER SVC BULLETIN #787A, DATED 8/15/85, ADDRESSED THE POSSIBILITY OF CRACKS DEVELOPING IN THE AREA OF THE FAILURE. IT RECOMMENDED THAT AFTER THE 1ST 1000 HRS IN SVC, TRUNNIONS BE INSPECTED AT INTERVALS NOT TO EXCEED 100 HRS UNTIL REPLACED. THE LAST ANNUAL INSPECTION WAS DATED 3/8/88, BUT THERE WAS NO LOGBOOK ENTRY TO INDC THE INSPECTIONS HAD BEEN COMPLETED. THE ACFT HAD FLOWN ONLY 4 HRS SINCE THE LAST INSPECTION.

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

LANDING GEAR,MAIN GEAR..FATIGUE




Contributing Factors

MAINTENANCE,SERVICE BULLETIN/LETTER..NOT FOLLOWED..OTHER MAINTENANCE PERSONNEL

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