On January 4, 1999, a Cessna 140 (registration N3585V) was involved in an aviation accident near Santa Barbara, CA. Investigators recorded the probable cause as: A loss of engine power due to an internal left magneto coil primary circuit short. Factors were insufficient altitude and inadequate terrain to make an emergency landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An airplane performing touch-and-go landings experienced a total loss of engine power at 150 feet. The pilot attempted to turn and maintain airspeed, but the aircraft nosed over into a marsh. Investigation found incorrect magneto timing and an inoperative left magneto.
Accident Description
The airplane was conducting touch-and-go landings. After lifting off and climbing on the runway heading, the engine abruptly lost power at 150 feet above ground level. The pilot attempted to execute a turn and lower the nose to maintain airspeed. The engine faltered, producing partial power, then cycled and produced no power. The pilot did not have sufficient altitude to reach the runway. The airplane nosed over and came to rest in a marsh located near the runway.
Engine Examination
Examination of the engine revealed that the right magneto timing was set at 17 degrees before top dead center on cylinder number one. The Lycoming engine data plate specifies that the engine-to-magneto timing should be set at 25 degrees. The left magneto was inoperative. Further investigation found that the primary coil circuit in the left magneto was internally shorted.
Maintenance Records
Review of the maintenance records disclosed that the last annual inspection was accomplished on May 5, 1998, approximately 40 flight hours prior to the accident. No entries were found detailing any maintenance on the magnetos after that annual inspection.