WPR11FA186

The pilot reported that during cruise flight he heard a loud noise from the engine compartment followed by an immediate loss of engine power. The pilot attempted to restart the engine with no success while diverting to the nearest airport. Upon realizing that he would be unable to reach the airport, he decided to land on an interstate highway. As he approached the highway, the pilot observed heavy traffic and decided to land on an adjacent service road. During the landing roll, the left wing struck a tree and the airplane ground looped, resulting in structural damage to both wings. A postaccident examination of the engine revealed that both sets of magneto points were not opening. Inspection of the single-drive dual magneto found that the cam followers on both sets of points were worn to the point that they could no longer open the contacts. The magneto had accumulated 603.7 hours at the time of the accident since installation and 92.56 hours since the most recent magneto timing adjustment. No further anomalies were noted during the examination of the engine that would have precluded normal operation.

HISTORY OF FLIGHT On April 5, 2011, about 1021 mountain standard time, a Cessna 177RG, N2637V, sustained substantial damage during a forced landing following a loss of engine power near Gila Bend, Arizona. The commercial pilot, sole occupant of the airplane, was not injured. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations 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. In a written statement, the pilot reported that during cruise flight at an altitude of about 8,500 feet mean sea level (msl), he heard a loud noise from the engine compartment followed by an immediate loss of engine power. The pilot stated that he attempted to restart the engine with no success while diverting to the nearest airport. The pilot stated that when he realized he was unable to make it to the airport, he decided to land on Interstate 8. As he approached the interstate, he observed a high amount of traffic, and decided to land on an adjacent service road. During the landing roll, the left wing struck a tree and the airplane ground looped. TESTS AND RESEARCH 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. Examination of the recovered Lycoming IO-360-A1B6D engine, serial number L-13979-51A, revealed that the engine 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. The magneto to engine timing was attempted to be verified, however, during the timing check, it was noted 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 revealed that the contacts were not opening due to cam follower wear. No further mechanical anomalies were noted during the examination of the recovered engine that would have precluded normal operation. ADDITIONAL INFORMATION Review of the aircraft maintenance logbooks revealed 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 entry within the maintenance logbook concerning the adjustment of the magneto was an entry dated October 20, 2008, at a tachometer time of 2,466.44 hours, noting that the magneto to engine timing was adjusted to 25 degrees before top dead center. The most recent annual inspection conducted on the airframe and engine was recorded within the airplanes maintenance logbooks on April 1, 2011, at a tachometer time of2,546.33 hours. Within the entry for the annual inspection, it was noted that the magneto to engine timing was "checked." The magneto had accumulated 603.7 hours at the time of the accident since installation, and 92.56 hours since the most recent magneto timing adjustment.