Cessna 177 N29304 accident near Glendale, Arizona

Probable cause

The loss of engine power due to vapor lock. Contributing to the accident was the high atmospheric temperature.

NTSB analysis

The pilot said that following a successful run up, he departed from the airport. During the climb, the engine began to experience a partial loss of power and the pilot believed that it was due to vapor lock. The pilot verified the cockpit settings and leaned the mixture. The engine returned to normal power. Approximately 30 seconds later it happened again so the pilot leaned the mixture again. Power returned, but then it happened a third time. The pilot contacted the tower because the airplane was not climbing. He requested a return to the airport and turned back. Just after making the turn, the engine lost total power. The pilot force-landed the airplane in a field and the airplane impacted a fence. During the accident sequence, the firewall was buckled and the right wing leading edge was damaged. Post accident examination of the airplane and test run of the engine revealed no mechanical anomalies. The temperature at the time of the accident was 102 degrees Fahrenheit. A condition known as vapor lock can occur when the engine heats the fuel lines and the fuel in the lines becomes a vapor. This tendency is increased if the fuel in the tank is warm, commonly as a result of high atmospheric temperatures. The fuel vapor can result in partial or complete interruption of fuel flow to the engine.

Text from the NTSB. Open the NTSB docket for SEA08CA180 for the full record.