NTSB Factual Report

On June 11, 2001, about 1520 eastern daylight time, a Piper PA-28-140, N43466, registered to Wilson Air Services, LLC, crashed during a forced landing following loss of engine power, shortly after takeoff from Lumpkin County-Wimpys Airport, Dahlonega, Georgia, while on a 14 CFR Part 91 personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane received substantial damage and the private-rated pilot received serious injuries. The flight originated from Dahlonega, Georgia, the same day, about 1500.

The pilot stated he had made a couple of takeoffs and landings at the Lumpkin County-Wimpys Airport, While taking off on runway 15, he performed a short field takeoff using 25 degrees of wing flaps. About half way down the runway he felt a loss of engine power and noticed he was not high enough to clear the high terrain in front of him. He decided to aim for a pasture to the right of the departure end of the runway. This is the last thing he recalls. The next thing he remembers is seeing the airplane wrecked in the airport building.

After the accident the engine was placed on a test stand under the supervision of NTSB personnel. The engine was started and ran for a few seconds while producing white smoke, and then quit. The engine was again started and produced about 1,500 rpm. The engine operated roughly. The engine was shutdown and the No. 3 cylinder was found to not have an elevated temperature. The No. 3 cylinder was removed and the exhaust valve head was missing. The piston had impact damage from the exhaust valve head and a piece of the exhaust valve head was found in the cylinder. Examination of the No. 3 exhaust valve remnants showed no part number was visible on the parts.

Metallurgical examination of the remains of the number 3 exhaust valve was performed by the NTSB Materials Laboratory, Washington, D.C. The fracture surface on the stem portion of the valve was on a flat transverse plane, with large scale ratchet marks suggestive of fatigue cracking. In addition, three fatigue regions with clear crack arrest positions were noted on the fracture adjacent to the exterior surface of the stem. The exterior surface of the stem in the vicinity of the fracture surface revealed a heavy oxide or deposit scale. (See NTSB Materials Laboratory Report.)

Logbook records show the engine was last overhauled at aircraft and engine total time 5,880 hours. At the time of the accident the aircraft and engine total time were 6,646 hours. Logbook records prior to December 12, 1995, had been lost. The engine overhaul had occurred prior to that date. No records concerning the engine overhaul were present in the remaining aircraft records. (See Aircraft and Engine Logbook Records.)

NTSB Probable Cause

The failure of the No. 3 exhaust valve due to fatigue cracking for undetermined reasons, which resulted in a partial loss of engine power and an in-flight collision with a building during an attempted forced landing to unsuitable terrain..