This August 2010 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Stinson Junior. Injuries: 1 Minor. Location: Lake Stevens, Wash. Aircraft damage: Substantial.
What reportedly happened: According to the pilot, the airplane had been in cruise flight for about 30 minutes when the engine lost power. Attempts to restart the engine were unsuccessful, so the pilot made a forced landing in an open field, during which the airplane hit a fence.
The post-accident investigation determined that the engine magneto switch had failed. The magneto was original equipment in the airplane, which was manufactured 79 years before the accident. The pilot reported no known maintenance history or malfunction of the magneto switch prior to the accident.
Probable cause: A total loss of engine power during cruise flight, which resulted from a magneto switch failure.
For more information: NTSB.gov NTSB Identification:WPR10LA432