NTSB Identification: LAX90FA008.
The docket is stored on NTSB microfiche number 42398.
Accident occurred Wednesday, October 11, 1989 in GOODYEAR, AZ
Probable Cause Approval Date: 09/09/1992
Aircraft: BEECH F33A, registration: N67536
Injuries: 3 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
DURING THE TAKEOFF INITIAL CLIMB, ONE PROPELLER BLADE SEPARATED AND THE RESULTING IMBALANCE CAUSED THE REMAINING PROPELLER BLADE AND HUB TO SEPARATE. WITNESSES SAW THE AIRCRAFT PITCH UP, THEN ENTER A RIGHT TURN, IN AN APPARENT MANEUVER TO RETURN TO THE RUNWAY. WITNESSES SAW THE AIRCRAFT BANK ANGLE CONTINUE TO STEEPEN UNTIL THE AIRCRAFT ROLLED OVER AND ENTERED A SPIN. 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 FERRULED 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.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: 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. A FACTOR IN THE ACCIDENT WAS THE OIL COVERED WINDSHEILD, WHICH HINDERED THE PILOT IN MAINTAINING OUTSIDE VISUAL REFERENCES DURING A LOW ALTITUDE MANEUVER.
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