On June 27, 2007, a Piper PA-12 (registration N78456) was involved in an aviation accident near Anchorage, AK. Investigators recorded the probable cause as: The malfunction of an engine magneto during cruise flight, which resulted in a partial loss of engine power, and an on-ground encounter with terrain. A factor associated with the accident was the high vegetation at the off-airport landing site. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A private pilot experienced engine roughness during cruise, executed a precautionary landing on a grass field, and the airplane nosed over, damaging wings and rudder. Post-accident examination found a fractured magneto housing.
Accident Details
A private certificated pilot was conducting a local personal flight under Title 14, CFR Part 91. During cruise flight, the engine began to run rough. The pilot was unable to restore smooth operation and decided to perform a precautionary landing on a grass-covered field. The grass was described as knee to waist high. During the landing roll, the airplane nosed over. The pilot reported that the wings and rudder sustained damage as a result of the nose-over.
Engine Examination
An aircraft mechanic examined the engine after the airplane was recovered. During a test run, the engine exhibited a malfunctioning magneto. The magneto was sent to a shop for further examination. A technician who inspected the magneto noted that the upper housing had fractured, which allowed the wire-lugs to float internally, causing the engine to run rough. The technician stated that the damage to the magneto did not appear to be a result of the accident and that such a failure of the upper housing was not uncommon in older airplanes.