NTSB Identification: LAX98FA068.
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Accident occurred Friday, January 09, 1998 in SALINAS, CA
Probable Cause Approval Date: 03/31/2000
Aircraft: Cessna 182P, registration: N8158M
Injuries: 1 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

During a night-time flight in marginal VFR conditions, the pilot radioed approach control that his aircraft's engine had begun running rough, losing power, and he was having difficulty maintaining altitude. Approach control vectored the pilot 14 miles back to the airport where he had previously completed an instrument approach. The pilot reported the runway in sight, however, the aircraft crashed on final approach 2 miles from the runway. A witness reported hearing the aircraft's engine as it approached, followed by 5 seconds of silence, and then the sound of impact. An annual inspection was completed on the aircraft about 2 weeks before the accident and this was believed to be the owner's first flight after the inspection. During the inspection, the Nos. 1, 3, and 4 cylinders were removed from the engine and repaired. Postaccident examination of the engine revealed that one of the two valve keepers had not been reinstalled on the No. 3 cylinder exhaust valve resulting in asymmetric loading of the remaining keeper. When that keeper fractured, the exhaust valve was released and entered the combustion chamber of the No. 3 cylinder where it contacted the piston. The consequential damage fractured the Nos. 3 and 4 pistons, the Nos. 3 and 4 connecting rods, and the crankcase.

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

A loss of engine power due to a missing valve keeper. Also causal was the failure by engine maintenance personnel during engine top overhaul to install the second valve keeper in the No. 3 cylinder exhaust valve and the failure of inspection personnel to detect the improper assembly.

Full narrative available

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