Cessna 182P N21048 accident near Mammoth Lakes, California

Probable cause

The total loss of engine power due to carburetor icing, which resulted from the pilot’s failure to use carburetor heat in cruise flight while operating in an area conducive to carburetor icing.

NTSB analysis

The commercial pilot reported that the airplane was in cruise flight at 12,500 ft mean sea level (msl) when he noticed a partial loss of engine power and that the No. 1 cylinder exhaust gas temperature had dropped from 1,450 to 1,300 degrees F. The pilot diverted to an airport about 10 miles away; however, the engine then experienced a total loss of power about 4,000 ft above ground level. The airplane was unable to reach the airport, so the pilot performed a forced landing on a dirt road, during which the firewall was substantially damaged and the right main landing gear collapsed.

A postaccident engine test run at various power settings revealed no mechanical failures or malfunctions that would have precluded normal operation. Weather conditions at the time of the accident at the airplane's cruise altitude of 12,500 ft msl were conducive to the formation of carburetor icing at glide and cruise power. During the on-site examination of the wreckage, the carburetor heat control was found in the "off" position. It is likely that the engine lost power due to carburetor ice and that the timely application of carburetor heat would have restored engine power.

Text from the NTSB. Open the NTSB docket for WPR14LA208 for the full record.