On August 9, 1992, an Air Tractor AT-401 (registration N1547P) operated by Morris, Gary & Connie was involved in an aviation accident near Parker, AZ. Investigators recorded the probable cause as: Fatigue fracture of a propeller blade originating from a notch in a previously reworked area. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During an aerial application swath run, 10 inches of a propeller blade separated. The pilot performed an emergency landing, but the aircraft nosed over after contacting rough terrain. Metallurgical examination revealed fatigue across 60% of the fracture surface, originating at a notch in a reworked area.
Accident Overview
The pilot was conducting an aerial application swath run when approximately 10 inches of a propeller blade separated from the aircraft. The pilot subsequently executed an emergency landing. Upon touchdown, the aircraft nosed over after colliding with rough and uneven terrain.
Examination Findings
A metallurgical examination of the fractured propeller blade disclosed the presence of fatigue across 60% of the fractured surface. The origin of the fatigue centered on a notch within a previously reworked area of the blade. The propeller blade had accrued 273 flight hours since it was overhauled.
Probable cause
Fatigue fracture of a propeller blade originating from a notch in a previously reworked area.