HESPERIA, CA, USA
N4820T
PIPER PA-28R-200
THE ENGINE SUSTAINED A TOTAL LOSS OF POWER WHILE IN CRUISE FLIGHT. THE PILOT WAS UNABLE TO NEGOTIATE THE SELECTED AIRPORT, AND THE AIRPLANE COLLIDED WITH A RAVINE DURING THE LANDING 1/2 MI FROM THE RUNWAY. ENGINE TEARDOWN EXAMINATION DISCLOSED THAT THE #2 EXHAUST VALVE FAILED IN FATIGUE. THE ENGINE WAS LAST OVERHAULED ABOUT 9 YRS BEFORE THE ACCIDENT, AND HAD ACCRUED ABOUT 1,443 HRS.
On May 26, 1993, at 2315 hours Pacific daylight time, a Piper PA28R-200, N4820T, crashed about 1/2 mile east of Hesperia Airport, Hesperia, California. The pilot was conducting a cross country visual flight rules personal flight. The airplane, registered to and operated by the pilot, sustained substantial damage. Neither the certificated private pilot nor his passenger was injured. Visual meteorological conditions prevailed. The flight departed Apple Valley Airport, Apple Valley, California, at about 2230 hours. The pilot reported that after leveling off at cruising altitude the engine began to "sputter, knock and then lost power." The pilot elected to land at Hesperia Airport. The airplane's altitude, however, was insufficient to negotiate the airport, and the airplane crashed west of a ravine, about 1/2 mile east of the airport. On June 30, 1993, the engine was examined at Lynn's Aircraft Engines, Inc., El Monte Airport, El Monte, California. Mr. Charles Little, Textron Lycoming, participated in the examination. Continuity of the gear and valve train assembly was established prior to disassembly of the engine. The disassembly examination disclosed that the number 2 cylinder exhaust valve head was partially missing. The fractured area displayed extensive beach marks which according to metallurgical data are consistent with fatigue. The corresponding cylinder head and piston dome displayed extensive foreign object damage; a piece of the exhaust valve was found embedded in the piston dome. The oil control ring was found seized in its respective land groove. The number 3 cylinder skirt area displayed three scalloped areas had been ground out. According to the Textron Lycoming representative, that grinding of the skirt area is not an authorized repair. The nos. 1, 3, and 4 cylinder heads and piston domes displayed misfiring signatures. The number 3 oil control ring was also found seized in its respective land groove. An unidentified red silicon material was found on several crankcase bolt holes and on the accessory case. The crankshaft gear and oil pump shaft displayed wear patterns consistent with only one side of the pump gears making contact. Light fretting signatures were found on the case half parting surface. The connecting rods, nos. 1, 3, and 4, displayed extensive pitting on the I-Beam section and around the cap area. The number 1 connecting rod is marked as the number 6 rod. The crankshaft main bearing and the connecting rod bearings displayed light scoring signatures. The connecting rods weights were found within the manufacturer's service limits. Carbon deposits were observed on the oil suction screen. Both top and bottom spark plugs on the number 2 cylinder sustained extensive foreign object damage. The remaining spark plugs displayed center electrode ovaling patterns. Both magnetos were examined at Roberts Aircraft Components, California City Airport, California City, California. Both magnetos operated normally. The fuel servo unit and the diaphragm fuel pump contained bluish colored fuel. The fuel pump operated normally during hand operation. Examination of the engine logbook revealed that the engine received a major overhaul on June 1, 1984. The engine total time at overhaul was 1,834 hours. At the time of the accident, the engine accrued 1,443 hours since it was overhauled and a total time of 3,277 hours.
FATIGUE FAILURE OF THE EXHAUST VALVE DUE TO INADEQUATE MAINTENANCE AND INSPECTION.
Source: NTSB Aviation Accident Database
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