On September 19, 1988, an Air Tractor AT301 (registration N31646) operated by Ben Bernard was involved in an aviation accident near Ferriday, LA. Investigators recorded the probable cause as: A crack in the number five cylinder of the engine during agricultural operations. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An agricultural airplane experienced an engine malfunction while conducting a swath run, prompting the pilot to jettison chemicals and execute a forced landing in a bean field with minimal crop impact.
What happened
The incident occurred while an agricultural aircraft was engaged in a standard swath run operation. During this phase of flight, the engine suffered a sudden malfunction. In response to the mechanical failure, the pilot initiated emergency procedures by releasing the load of chemical agents carried in the hopper. Following the jettisoning of the payload, the pilot executed a forced landing in an adjacent bean field.
The investigation
A teardown inspection of the engine was conducted to determine the root cause of the failure. Examination revealed a structural crack within the number five cylinder. Specifically, the fracture extended from one spark plug hole to the adjacent spark plug hole within that cylinder block. Despite the presence of this crack, further analysis indicated that the damage did not interfere with or affect the operation of the engine valves.
Findings
The mechanical failure resulted in substantial damage to the aircraft structure. However, the impact on the surrounding environment was minimal. The landing caused very little damage to the bean crop in the field where the aircraft came to rest.
Probable cause
A crack in the number five cylinder of the engine during agricultural operations.