On April 5, 1990, an Air Tractor AT-401 (registration N1015A) was involved in an aviation accident near Hornersville, MO. Investigators recorded the probable cause as: The failure of the number 9 cylinder, which resulted in an in-flight engine failure and a subsequent emergency landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During an aerial application flight, the engine failed shortly after takeoff, forcing an emergency landing in a muddy field that resulted in substantial damage.
What happened
The pilot reported that shortly after takeoff, while conducting an aerial application operation, the aircraft's engine experienced a sudden failure. Unable to maintain altitude or return to the departure airport, the pilot executed an emergency landing in an adjacent soft, muddy farm field. The impact caused the aircraft to nose over, resulting in substantial damage to the airframe.
The investigation
A post-accident examination of the engine revealed that the #9 cylinder had failed. This mechanical failure was identified as the primary reason for the loss of power during the critical phase of flight immediately following departure.
Probable cause
The failure of the number 9 cylinder, which resulted in an in-flight engine failure and a subsequent emergency landing.