Accident Details
On August 29, 2012, at approximately 1530 central daylight time, an Air Tractor AT-301 airplane, registration N23960, sustained substantial damage during a forced landing near Ralls, Texas. The pilot, who was the sole occupant, was not injured. The aircraft was registered to and operated by Beta Ag, Inc., under 14 Code of Federal Regulations Part 137 for agricultural application flights. The flight departed from Crosbyton Municipal Airport (8F3) in Crosbyton, Texas, at about 1515 on a local operation. Day visual meteorological conditions prevailed, and no flight plan was filed.
Engine Failure and Forced Landing
According to the pilot, the engine began to sputter and then experienced a complete loss of power. The pilot executed a power-off landing to a soft dirt trail in a cotton field. During the landing, the airplane nosed over and came to rest inverted. The pilot was able to exit the aircraft without assistance. There was a substantial amount of fuel on board, but no fuel spill or postimpact fire occurred.
Postaccident Examination
Examination of the Pratt and Whitney R-1340 engine, serial number P 326932, revealed a fatigue failure of the rocker arm journal casting of the rocker arm cap. This failure resulted in the complete separation of the exhaust valve rocker arm.