NTSB Identification: IAD01LA046.
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Accident occurred Sunday, April 22, 2001 in King George, VA
Probable Cause Approval Date: 05/13/2003
Aircraft: Piper PA-32R-300, registration: N40066
Injuries: 4 Minor.

NTSB investigators may have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The airplane was in cruise flight at 3,500 feet in the vicinity of the Potomac River when the airplane experienced a partial loss of engine power. The pilot said he checked the magnetos and engine controls, and experienced a slight restoration of power when he adjusted the mixture. Within 3 minutes, there was a total loss of engine power. The pilot turned away from the river, and performed a forced landing to a farm pasture. Examination of the airplane at the scene revealed that the # 3 cylinder was loose on the crankcase, and the number 3 intake tube was not installed, and rested in the bottom of the engine compartment. The #3 exhaust riser was found separated at the flange. The flange was found loose, as the two nuts were not tight, with one nut having no washer or lock washer installed. Further examination revealed the 2 case studs and 2 thru studs along the bottom of the # 3 cylinder were broken off. The cylinder was removed and visually examined. The cylinder skirt exhibited chafing and scratching. There was corresponding scratching to the cylinder case pad material. Examination of the fractured cylinder studs revealed fracture surfaces with features consistent with fatigue. The engine was overhauled 14 years and 917 flight hours prior to the accident, and no cylinders had been removed during that time. The engine manufacturer recommended that the engine be overhauled every 2,000 hours or 12 years, whichever occurred first.

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

The failure of cylinder case and thru studs due to fatigue, which resulted in a loss of engine power over unsuitable terrain.

Full narrative available

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