Probable cause
The loss of two securing bolts that allowed the left magneto to move around, which disrupted the spark timing and resulted in the engine losing total power.
NTSB analysis
The private pilot was practicing crop-dusting maneuvers when the engine lost total power; he performed a forced landing in an open, muddy field. The airplane nosed over and sustained substantial damage. Postaccident examination of the engine revealed that two of three bolts that secured the left magneto had come loose and were missing. The safety wire was broken, and the Sims coupling was heavily damaged. The magneto could easily be moved around, which disrupted the spark timing and resulted in a total loss of power.
Text from the NTSB. Open the NTSB docket for CEN18LA357 for the full record.
Event
- Date
- Aug 29, 2018
- Type
- Accident
- Place
- Opelousas, Louisiana
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Grumman G164
- N-number
- N956X
- Category
- Airplane
- Year built
- 1968
- Damage
- Substantial
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Personal
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.