On October 11, 1989, a Beech F33A (registration N67536) operated by Airline Training Center was involved in an aviation accident near Goodyear, AZ. Investigators recorded the probable cause as: THE INFLIGHT SEPARATION OF ONE PROPELLER BLADE DUE TO A FATIGUE FRACTURE OF UNDETERMINED ORIGIN, AND FAILURE OF THE PILOT TO MAINTAIN CONTROL OF THE AIRCRAFT DURING AN ATTEMPT TO RETURN TO THE RUNWAY. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 3 related events involving the same aircraft type or operator are linked below.
During takeoff initial climb, a propeller blade separated due to fatigue fracture, causing the remaining blade and hub to separate. The aircraft pitched up, entered a right turn, rolled over, and spun.
Incident Description
During the takeoff initial climb, one propeller blade separated from the aircraft. The resulting imbalance caused the remaining propeller blade and hub to also separate. Witnesses observed the aircraft pitch up, then enter a right turn, in what appeared to be a maneuver to return to the runway. The bank angle continued to steepen until the aircraft rolled over and entered a spin.
Examination Findings
Metallurgical examination of the failed blade revealed that it separated due to a fatigue fracture in the first full thread of the threaded shank portion, which fitted inside a ferrule fitting. Extensive metallurgical examination of the fracture failed to identify the initiating defect in the fatigue fracture. On-site examination revealed that the windshield was heavily coated with engine oil.