NTSB Identification: WPR10LA465
14 CFR Part 91: General Aviation
Accident occurred Tuesday, September 21, 2010 in Visalia, CA
Probable Cause Approval Date: 12/13/2011
Aircraft: MOONEY M20C, registration: N6090Q
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

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.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

A partial loss of engine power during takeoff, which resulted from the failure of the spark plug retention mechanism.

Full narrative available

Index for Sep2010 | Index of months