Cessna 177RG N2637V accident near Gila Bend, Arizona

Probable cause

A total loss of engine power during cruise flight due to both sets of magneto points failing to open as a result of excessive wear of the magneto cam followers.

NTSB analysis

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.

Text from the NTSB. Open the NTSB docket for WPR11FA186 for the full record.