History of Flight
On April 5, 2011, at approximately 1021 mountain standard time, a Cessna 177RG, registration N2637V, sustained substantial damage during a forced landing following a loss of engine power near Gila Bend, Arizona. The commercial pilot, who was the sole occupant, was not injured. The airplane was registered to and operated by the pilot under 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the cross-country flight that originated from Ramona, California, with an intended destination of Sierra Vista, Arizona.
According to the pilot's written statement, during cruise flight at about 8,500 feet mean sea level, he heard a loud noise from the engine compartment, followed by an immediate loss of engine power. The pilot attempted to restart the engine without success while diverting to the nearest airport. When he realized he could not reach the airport, he decided to land on Interstate 8. Upon approaching the interstate, he observed heavy traffic and opted to land on an adjacent service road. During the landing roll, the left wing struck a tree, and the airplane ground looped.
Examination Findings
Examination of the airplane by local law enforcement revealed that the left and right wings were bent upward just outboard of the flap-aileron junction. The airplane was recovered to a secure location for further examination.
The recovered Lycoming IO-360-A1B6D engine, serial number L-13979-51A, remained attached to the airframe via all mounts. The top spark plugs were removed, and the engine crankshaft was rotated by hand. Rotational continuity was established throughout the engine and valve train. Thumb compression was obtained on all four cylinders. Attempts to verify magneto-to-engine timing revealed that the magneto points were not opening to trigger the test box. The magneto was subsequently removed and disassembled. Examination of the single-drive dual magneto showed that the contacts were not opening due to cam follower wear. No other mechanical anomalies that would have precluded normal operation were noted.
Maintenance History
Review of the aircraft maintenance logbooks indicated that the Bendix D4LN-3000 magneto, serial number 510951, had been installed on October 23, 2003, at a tachometer time of 1,955.3 hours. The most recent logbook entry concerning the magneto was an adjustment on October 20, 2008, at a tachometer time of 2,466.44 hours, timing set to 25 degrees before top dead center. The most recent annual inspection, recorded on April 1, 2011, at a tachometer time of 2,546.33 hours, noted that the magneto timing was "checked." At the time of the accident, the magneto had accumulated 603.7 hours since installation and 92.56 hours since the most recent timing adjustment.