Probable cause
The total loss of engine power due to a fatigue failure of the rocker arm journal casting of the rocker arm cap.
NTSB analysis
The pilot reported that, while conducting aerial application operations, the engine sputtered and then experienced a complete loss of power. During the forced landing, the airplane nosed over and then came to rest inverted. A postaccident examination of the engine revealed a fatigue failure of the rocker arm journal casting of the rocker arm cap, which resulted in the complete separation of the rocker arm and failure of the exhaust valve.
Text from the NTSB. Open the NTSB docket for CEN12LA589 for the full record.
Event
- Date
- Aug 29, 2012
- Type
- Accident
- Place
- Ralls, Texas
- Highest injury
- Minor
- Minor injuries
- 1
- Weather
- Visual (VMC)
- Light
- Day
Air Tractor Inc AT-301
- N-number
- N23960
- Category
- Airplane
- Damage
- Substantial
- Operating rule
- Part 137 (agricultural)
- Purpose of flight
- Aerial application
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.