What happened
The incident occurred while the aircraft was engaged in an aerial application mission. During the operation, the pilot reported that the engine began to shake violently. The mechanical instability caused the airplane to lose its ability to maintain altitude effectively. In response to the power loss, the pilot initiated a forced landing procedure, targeting a nearby soft field for touchdown.
Upon contact with the ground, the aircraft sank into the soft terrain, which contributed to the nose-over attitude of the plane after it came to rest.
The investigation
An inspection was conducted by an FAA inspector to determine the mechanical cause of the engine failure. The examination revealed a significant structural defect within the engine assembly.
Findings
The investigation identified that the engine had sustained damage that directly resulted in the loss of power during flight. Specifically, there was a crack in the number 8 cylinder head. This mechanical failure prevented the engine from producing sufficient thrust to sustain level flight, necessitating the emergency landing.
The primary causal factor was a crack in the #8 cylinder head.