NTSB Factual Report

On November 16, 2001, about 1808 eastern standard time, a Piper PA-24-250, N8183P, registered to an individual, collided with a ditch while making a forced landing following loss of engine power near Peachtree City, Georgia, while on a 14 CFR Part 91 business flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane received substantial damage, and the commercial-rated pilot received minor injuries. The flight originated from Hampton, Georgia, the same day, about 1750.

The pilot stated that on November 16, 2001, he prepared to depart from his home airport, McCollum Field. As he performed an engine runup, he found the left magneto was not operating. He returned to the ramp and his mechanic disconnected and then reconnected the magneto "P" leads. The left magneto began to work. He departed McCollum Field and went to Peachtree City. He then flew to Tara Field, at Hampton, Georgia. When leaving Tara Field, he found that the left magneto was again inoperative. He called his mechanic and was told to disconnect the "P" leads and fly home. With the "P" leads disconnected, he could not check the magnetos. During takeoff, the engine appeared to develop full power. The EGT was normal. About 5 minutes after departure, the EGT pegged out high and one of the magnetos appeared to have quit. About a minute later, the engine quit. Atlanta Approach gave him radar vectors to the closest airport, Peachtree City. He could not make it to the airport and landed in a field with the gear down and full wing flaps extended. During rollout in the field, the airplane collided with a drainage ditch. The landing gear collapsed and the airplane slid to a stop. The magnetos had been overhauled by a local mechanic about 100 flight hours before the accident. (See record of telephone conversation.)

A mechanic for the company that recovered the airplane from the crash site stated he was present when the engine of N8183P was run on the airplane after the accident. The FAA and NTSB were present. During examination prior to running the engine, the "P" lead was disconnected from one magneto and the spark retard lead was disconnected from the other magneto. They reconnected the leads and the engine was started. Only one magneto was operating. The engine was operated to 1,500 RPM with a club propeller in the feathered position. The was no evidence of mechanical failure or malfunction of the engine assembly. The magnetos were taken by the NTSB for further testing. (See record of telephone conversation.)

A engineer at Teledyne Continental Motors, the magneto manufacturer, stated he examined the magnetos from N8183P with an NTSB investigator. The left magneto has a "P" lead and a spark retard lead, which is used for starting. The right magneto did not have the spark retard lead, only a "P" lead. The left magneto condenser was inoperative causing the magneto to not operate. The right magneto operated normally. With one magneto inoperative, the exhaust gas temperature will become elevated due inefficient burning in the cylinder which carries over into the exhaust area. When you remove the "P" lead on these magnetos, they actually ground internally and become inoperative. Sometimes contamination prevents them from grounding immediately when the "P" lead is removed, but they eventually ground and become inoperative. He believes that with the spark retard disconnected on the left magneto and the "P" lead disconnected on the right magneto, that the left and right magnetos operated for takeoff due to the condenser working at this time on the left magneto and that the "P" lead internal grounding had contamination that prevented it from grounding immediately after removal of the "P" lead. Takeoff was normal at full power due to both magnetos working. Then either the left magneto quit due the condenser failing or the right quit due to it becoming internally grounded. The exhaust gas temperature went high and a small loss of power could be noted. Then the second magneto quit resulting in failure of the engine.

NTSB Probable Cause

The pilot’s attempted operation of the aircraft with known deficiencies in the engine ignition system resulting in failure of the engine due to ignition system failure and damage to the airplane during the subsequent forced landing.