Accident Summary
The pilot was conducting an agricultural spraying operation over a cotton field at an altitude of approximately 300 feet. About one and a half hours into the flight, while initiating a right turn, the engine lost power. The pilot attempted a forced landing, during which the right wing collided with a tree. Subsequently, the airplane spun to the right, struck the ground nose-first, bounced several times, and came to rest.
Engine Examination
A post-accident examination of the engine revealed an interruption of the direct drive fuel control (DDFC) gear-train. The interruption was caused by a loss of mechanical contact between the teeth of the second and third DDFC gears. The loss of contact was attributed to excessive loading on the forward gear teeth of the third DDFC gear, which resulted in the loss of material from that gear.
Investigation Findings
Investigators examined the engine components for assembly, dimensional, or material defects that could have contributed to the excessive loading or the gear interference. No such defects were identified. The exact cause of the excessive loading remained undetermined, but the immediate failure mechanism was the loss of material from the third DDFC gear teeth, leading to the gear-train interruption and subsequent engine power loss.