What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
On [date], Cessna 172 privacy data omitted was conducting a training flight with a flight instructor and student pilot when the engine experienced a total loss of power. Restart attempts were unsuccessful, and the instructor conducted a precautionary landing at Twin Hawks Airpark (AZ63) without further incident. The aircraft was not damaged during the landing.
The engine was removed and sent to an engine overhaul facility for teardown and evaluation. The teardown revealed a sheared crankshaft gear dowel pin, which allowed the crankshaft gear to move out of position and prevented the magnetos from operating correctly, resulting in the loss of engine power. Damage was noted to the crankshaft gear and associated components.
Maintenance personnel advised that the observed damage could be consistent with a previous propeller strike; however, the aircraft owner reported the engine had not experienced a propeller strike since overhaul. The ASI reviewed the aircraft maintenance records and found no evidence of a propeller strike. The engine was approximately 100 hours from the manufacturer's recommended overhaul interval.
The investigation was unable to definitively determine the cause of the crankshaft gear dowel pin failure.
As the FAA filed it
ON [DATE], CESSNA 172 ^PRIVACY DATA OMITTED^ WAS CONDUCTING A TRAINING FLIGHT WITH A FLIGHT INSTRUCTOR AND STUDENT PILOT WHEN THE ENGINE EXPERIENCED A TOTAL LOSS OF POWER. RESTART ATTEMPTS WERE UNSUCCESSFUL, AND THE INSTRUCTOR CONDUCTED A PRECAUTIONARY LANDING AT TWIN HAWKS AIRPARK (AZ63) WITHOUT FURTHER INCIDENT. THE AIRCRAFT WAS NOT DAMAGED DURING THE LANDING.
THE ENGINE WAS REMOVED AND SENT TO AN ENGINE OVERHAUL FACILITY FOR TEARDOWN AND EVALUATION. THE TEARDOWN REVEALED A SHEARED CRANKSHAFT GEAR DOWEL PIN, WHICH ALLOWED THE CRANKSHAFT GEAR TO MOVE OUT OF POSITION AND PREVENTED THE MAGNETOS FROM OPERATING CORRECTLY, RESULTING IN THE LOSS OF ENGINE POWER. DAMAGE WAS NOTED TO THE CRANKSHAFT GEAR AND ASSOCIATED COMPONENTS.
MAINTENANCE PERSONNEL ADVISED THAT THE OBSERVED DAMAGE COULD BE CONSISTENT WITH A PREVIOUS PROPELLER STRIKE; HOWEVER, THE AIRCRAFT OWNER REPORTED THE ENGINE HAD NOT EXPERIENCED A PROPELLER STRIKE SINCE OVERHAUL. THE ASI REVIEWED THE AIRCRAFT MAINTENANCE RECORDS AND FOUND NO EVIDENCE OF A PROPELLER STRIKE. THE ENGINE WAS APPROXIMATELY 100 HOURS FROM THE MANUFACTURER'S RECOMMENDED OVERHAUL INTERVAL.
THE INVESTIGATION WAS UNABLE TO DEFINITIVELY DETERMINE THE CAUSE OF THE CRANKSHAFT GEAR DOWEL PIN FAILURE.
Other reports on N4337F · 1
Matched to the same aircraft by N-number and date.