Mechanical & Engine Failure · NTSB ERA16FA023
MOONEY M20M — Worcester, MA
| Date | October 24, 2015 |
| Location | Worcester, MA |
| Aircraft | MOONEY M20M |
| Purpose of flight | Personal |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Emergency descent Loss of control in flight |
| Pilot age | 66 |
| Pilot total time | 7,230 hrs · High time |
| Time in type | Unknown |
| Fatalities | 1 |
Probable cause
NTSB findings
- Aircraft-Aircraft power plant-Engine (reciprocating)-Recip engine power section-Failure - C
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Angle of attack-Not attained/maintained - F
- Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - F
What happened
The airline transport pilot was departing on a personal local flight in his airplane when the airplane's engine lost total power. Review of airport security video revealed that, after takeoff, the airplane reached an altitude of about 200 ft before turning right and reversing direction. The airplane subsequently stalled, rolled to the right, and descended uncontrolled into trees. It is likely that the pilot reversed direction to return to the airport but failed to maintain adequate airspeed while maneuvering, which resulted in the airplane exceeding its critical angle of attack, an aerodynamic stall, and loss of control. Examination of the engine revealed that the crankshaft had failed due to fatigue cracking between the No. 5 and No. 6 cheeks. The cracking pattern suggested that numerous overstress conditions of relatively short durations acted to initiate the fatigue cracks, but the cause for this overstress could not be determined.