Probable cause
The separation of the piston connecting rod from the crankshaft due to inadequate installation from a mechanic, resulting in a total loss of engine power.
NTSB analysis
The pilot was conducting a formation flight when the airplane’s engine experienced a loss of power. The pilot and his instructor then conducted a forced landing to a runway and landed long, with the airplane departing the surface and coming to rest in a field. Post accident examination revealed that the number three piston connecting rod cap separated from the piston connecting rod when the hardware came loose and the connecting rod disconnected during flight. Maintenance records showed that the engine had been overhauled several years prior to the accident. It is likely that the mechanic did not properly install the connecting rod bolts and nuts, which resulted in the number three piston connecting rod disconnecting during flight, and subsequent loss of engine power.
Text from the NTSB. Open the NTSB docket for ERA12LA422 for the full record.
Event
- Date
- Jun 28, 2012
- Type
- Accident
- Place
- Mc Kinnon, Tennessee
- Nearest airport
- Houston County Airport (M93)
- Highest injury
- Serious
- Serious injuries
- 1
- Minor injuries
- 1
- Weather
- Visual (VMC)
- Light
- Day
Mooney M20J
- N-number
- N174JB
- Category
- Airplane
- Damage
- Substantial
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Instructional
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.