Maule M-5-235C N9254E accident near Stanley, Idaho

Probable cause

The pilot’s failure to use carburetor heat in weather conditions conducive to carburetor icing, resulting in a partial loss of engine power and a forced landing during which the airplane struck an object and nosed over.

NTSB analysis

The pilot initiated a descent to the remote airstrip with the intention of performing a low approach to check the runway surface then landing if conditions allowed. About 500 ft before the runway threshold, the pilot applied full engine power, and the engine responded but then began to progressively lose power. He turned on the carburetor heat, confirmed that the engine mixture was set correctly, and began to turn the airplane away from rising terrain. The airplane would not climb, and he maneuvered it through an adjacent canyon, at which time the engine started to regain power. Due to rising terrain, the pilot had limited options to turn around the airplane, so the pilot performed a forced landing. During the landing flare, the airplane struck a log and nosed over.

Postaccident examination revealed no anomalies with the engine that would have precluded normal operation. Weather conditions at the time of the flight were conducive to serious carburetor icing at cruise power. The pilot did not turn on carburetor heat until after the engine started to lose power, so it is likely that pilot’s failure to use carburetor heat earlier in the flight caused carburetor icing that led to the partial loss of engine power.

Text from the NTSB. Open the NTSB docket for WPR21LA212 for the full record.