Accident Details
The pilot was starting the 4th load of 12 planned loads. He topped off the hopper with 1,500 pounds of 46% UREA fertilizer before departing from a 4,000-foot long by 100-foot wide dirt airstrip. During the takeoff roll, as the airplane approached lift-off, the right main landing gear axle and wheel separated from the landing gear strut. The strut then dug into the runway and separated from the airplane. The pilot reported that the engine and propeller subsequently dug into the runway, causing the airplane to nose over. The airplane came to rest in an inverted position.
Examination Findings
An FAA inspector examined the aircraft and found that two bolts from the left main landing gear, part numbers AN 509-616-35 and MS 20008H-22, were fractured. The fractures showed evidence of fatigue. The aircraft had accumulated a total of 11,006 hours since new; however, the time since installation of the failed bolts could not be established.