Probable cause
A partial loss of engine power during takeoff, which resulted from the failure of the spark plug retention mechanism.
NTSB analysis
The pilot applied full engine power, took off, and climbed to about 300 feet above the runway. The engine suddenly lost partial power, and the pilot elected to return to the airport for a forced landing. The airplane’s altitude was insufficient to complete the turn, and the airplane impacted the ground adjacent to the departure runway, substantially damaging the right wing. An examination of the engine revealed that the retention mechanism for the bottom No. 3 spark plug failed and the spark plug had blown out of its cylinder. Its failure appeared related to excessive wear and the loosening over time of the Heli-Coil insert. According to the Federal Aviation Administration, evidence of the Heli-Coil’s loosening would not, necessarily, have been apparent to a mechanic during routine maintenance.
Text from the NTSB. Open the NTSB docket for WPR10LA465 for the full record.
Event
- Date
- Sep 21, 2010
- Type
- Accident
- Place
- Visalia, California
- Nearest airport
- Visalia Municipal (VIS)
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Mooney M20C
- N-number
- N6090Q
- Category
- Airplane
- Damage
- Substantial
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Personal
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.