On September 22, 1995, a Grumman G-164A (registration N9700) was involved in an aviation accident near Lynchburg, SC. Investigators recorded the probable cause as: The right magneto timing had been lost because the rear attachment base had broken, permitting the magneto to shift. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During a return flight from crop spraying, the engine lost power. The pilot executed a forced landing in a soybean field, but the aircraft nosed over after landing gear caught on crops. Postcrash inspection revealed a broken magneto attachment base.
Incident Overview
A pilot conducting crop spraying operations experienced engine roughness while returning from a field. After checking both magnetos, the engine subsequently lost power. Despite attempts to restart, the engine remained inoperative, prompting the pilot to choose a soybean field for an emergency landing.
Landing and Nose-Over
During the landing flare, the aircraft's landing gear was caught by the soybean crop, which was approximately 5 feet high. This caused the aircraft to nose over.
Postcrash Findings
Examination after the accident revealed that the right magneto had lost its timing. The timing loss occurred because the rear attachment base of the magneto had broken, allowing the magneto to shift position.
Probable cause
The right magneto timing had been lost because the rear attachment base had broken, permitting the magneto to shift.