On April 25, 1987, a Cessna 500 (registration N82AT) was involved in an aviation accident near Willoughby, OH. Investigators recorded the probable cause as: Uncontained failure of the left engine impeller due to fatigue cracks on its pressure face. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During takeoff roll, a loud bang preceded uncontained failure of the left engine impeller. The aircraft stopped on the runway. Investigation discovered fatigue cracks on the impeller's pressure face.
Incident Description
The aircraft had been flown for over four hours on personal business for the owner. The pilots stopped at LNN to drop off passengers. The start and taxi were normal for the positioning flight back to the home base. During the takeoff roll, as the engine RPM reached 80-85% toward the target of 95.7%, the pilots reported hearing a loud bang. The copilot observed the left engine fan stage separate from the aircraft, arc upward and to the right, then strike the ground at the edge of the runway and bounce onto the grass 125 feet to the right of the runway. The pilot stopped the aircraft on the runway.
Investigation Findings
Inspection of the aircraft and engine revealed an uncontained failure of the left engine impeller. Further inspection of the impeller showed fatigue cracks on its pressure face, which led to the failure.
Conclusion
The uncontained failure of the left engine impeller was caused by fatigue cracks on the pressure face of the impeller.
Probable cause
Uncontained failure of the left engine impeller due to fatigue cracks on its pressure face.