Incident Overview
On May 15, 2008, at approximately 1510 Pacific daylight time, an Ercoupe 415-C (registration N99180) experienced a loss of engine power during cruise flight, leading to a forced landing in Penngrove, California. The sport pilot and his passenger were not injured. The airplane was operated under Title 14 Code of Federal Regulations Part 91 and was on a local personal flight that had departed from Petaluma Municipal Airport in Petaluma, California, around 1450. Visual meteorological conditions were present, and no flight plan had been filed.
Pilot Report
According to the Sonoma County Sheriff's Department, the pilot reported that while in cruise flight, the oil pressure gauge began to fluctuate erratically, with the needle "bouncing up and down." Seconds later, the engine started to cut out and sputter. The pilot initially headed back toward Petaluma Airport, but the engine lost total power, forcing the pilot to execute a landing in an alfalfa field located approximately 4.5 miles northwest of the airport.
Aircraft Damage
During the landing roll in 2- to 3-foot-tall grass, the airplane skidded sideways, causing the tail to dig into the ground. The tail cone was buckled, and the right vertical stabilizer and rudder were bent. The aircraft sustained substantial damage.
Post-Accident Examination
Federal Aviation Administration (FAA) inspectors examined the airplane. They found that both magnetos had frayed primary wires (P-leads) at the magnetos, which could have been shorting out and intermittently killing the ignition system. The inspectors noted numerous additional maintenance discrepancies, but stated that none of these would have contributed to a loss of engine power. The airplane's most recent annual inspection had been completed on March 19, 2008.