Accident Sequence
The pilot was applying fertilizer to an agricultural field when the airplane experienced a partial loss of engine power. While in a climbing turn at about 150 feet above ground level, the pilot felt the airplane shake as if approaching a stall. Advancing the throttle did not restore normal engine sound or allow the airplane to maintain altitude. The pilot, then over an orchard, directed the airplane toward one of the fields he was working. He reported that while over that field and fighting stall buffet, the airplane ceased flying, spun over to the right inverted, and nosed down to the ground 50 feet below. The pilot exited the airplane, and a post-impact fire ensued.
Post-Accident Examination
A Federal Aviation Administration (FAA) inspector performed a post-accident examination of the airplane's engine at the operator's facility. The engine, a Continental IO-520-D, had folded under the wreckage against the ground, which provided protection from the post-accident fire. Extensive heat damage was identified around cylinder number 5, which included local melting of the aluminum around the rocker cover and intake manifold. The number 5 cylinder fuel injector line was found free of the fuel injector nozzle, and the injector line b-nut was only finger tight.
Maintenance History
Examination of the airplane's maintenance logbook revealed that the engine oil cooler had been removed and replaced on March 12, 2004, approximately 36 flight hours prior to the accident. The FAA inspector noted that a common practice used by mechanics is to move or adjust the number 5 cylinder fuel injector line in order to install or uninstall the engine oil cooler.