Piper PA-18-150 N278Z accident near King Cove, Alaska

Probable cause

A total loss of engine power due to the pilot's failure to use carburetor heat in conditions conducive to carburetor ice.

NTSB analysis

The pilot was doing aerial surveillance on a federal public use flight when the accident occurred. The pilot reported that he was flying at a reduced airspeed and engine rpm without using carburetor heat, and that when he further reduced the rpm the engine lost power. He said he immediately added carburetor heat, full throttle, and full rich mixture. He said that some power was restored, but the engine then quit. Unable to restart the engine, he concentrated on landing the airplane on a rough and uneven road. During the landing roll he was unable to maintain directional control and the airplane ran into a ditch where both wings struck the ground. The pilot said that prior to the loss of engine power there were no mechanical problems with the airplane. The airplane sustained substantial damage to both wings and the fuselage. During a subsequent engine run the engine started and ran normally. The carburetor was removed and sent to a maintenance shop where it was determined that the carburetor functioned normally, and all wear was within the serviceable limits. A carburetor icing chart showed that the operating conditions were conducive to serious carburetor icing at any power setting.

Text from the NTSB. Open the NTSB docket for ANC10TA017 for the full record.