Accident Summary
On July 29, 2009, at approximately 0415 Pacific daylight time, an Air Tractor Inc. AT-301, registration N23189, experienced a loss of engine power and subsequently made a forced landing about 5 nautical miles northwest of Firebaugh, California. The aircraft sustained substantial damage during the landing. The commercial pilot, who was the sole occupant, was not injured. The flight was conducted under visual meteorological conditions in accordance with 14 Code of Federal Regulations Part 137 for aerial application purposes. No flight plan was filed. The aircraft had departed from a private airstrip located about 4 miles east of Dos Palos, California, at 0410.
Pilot Report
According to a statement provided by the pilot to the Safety Board investigator-in-charge, the engine lost power while the pilot was approaching the field to be sprayed. After initiating a forced landing, the airplane struck an angle ditch and nosed over, resulting in substantial damage to the empennage.
FAA Inspection
A Federal Aviation Administration inspector who responded to the accident site reported that upon arrival, no fuel was present in either wing tank. The inspector could not hear any fuel sloshing in the tanks, and when the fuel caps were opened, no fuel exited and no fuel fumes were detected. When asked by the inspector who fueled the airplane, the pilot stated that company personnel performed fueling, as they always handled both fuel and pesticide. The pilot indicated that typically 30 gallons of fuel were placed in each tank. The pilot provided a fuel load sheet showing that the airplane was fueled prior to the fourth load after a change of airstrips at 0300; the accident occurred on that fourth load.
Engine Examination
A certificated FAA airframe and powerplant mechanic conducted an inspection of the engine and found no abnormalities, either externally or internally. The mechanic reported that valve operation was normal with engine rotation, all nine cylinders maintained adequate compression, the blower impeller turned at a 10-to-1 ratio with engine rotation, and the crankshaft was within limits after being dialed. A serviceable propeller was installed, and an engine run at full power produced normal manifold pressure and RPM; the magnetos checked normal. After shutdown, the oil screen was removed and showed no foreign metal or debris. The mechanic concluded that the engine was airworthy for normal operation.