NTSB Identification: FTW90LA010.
The docket is stored on NTSB microfiche number 42160.
Accident occurred Thursday, October 12, 1989 in HENDERSON, TX
Probable Cause Approval Date: 07/22/1992
Aircraft: PIPER PA-28-140, registration: N6636W
Injuries: 2 Minor.

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 AIRPLANE EXPERIENCED A HARD LANDING AFTER AN ENGINE FAILURE IN CRUISE FLIGHT AND THE ENSUING FORCED LANDING IN ROUGH TERRAIN. THE ENGINE FAILURE WAS DETERMINED TO BE THE RESULT OF THE FAILURE OF THE #3 EXHAUST VALVE. HOWEVER, THE ROOT CAUSE OF THE VALVE FAILURE COULD NOT BE DETERMINED METALLURGICALLY DUE TO SECONDARY DAMAGE TO ALL OF THE FRACTURE SURFACES. THE PILOT HAD RECENTLY PURCHASED THE AIRPLANE AND THE ENGINE WAS 661 HOURS PAST THE RECOMMENDED OVERHAUL TIME. A SERVICE INSTRUCTION CRITICAL TO THE REPLACEMENT OF THE EXISTING VALVES WITH HEAVIER DUTY VALVES HAD NOT BEEN COMPLIED WITH PRIOR TO THE SALE OR THE ACCIDENT. THE PURCHASER WAS NOT AWARE OF THE SERVICE INSTRUCTION.

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

THE LOSS OF ENGINE POWER AS A RESULT OF A FAILURE OF THE NUMBER 3 EXHAUST VALVE DUE TO UNDETERMINED REASONS. FACTORS INVOLVED IN THE ACCIDENT WERE THE PREVIOUS OWNER'S DELAY IN OVERHAULING THE ENGINE AND HIS FAILURE TO ADHERE TO THE MANUFACTURER'S RECOMMENDED MAINTENANCE INSTRUCTIONS AND ROUGH TERRAIN IN THE TOUCHDOWN AREA OF THE EMERGENCY LANDING.

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