WPR21LA212

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.

On May 29, 2021, about 1100 mountain daylight time, a Maule M-5-235C, N9254E, was substantially damaged when it was involved in an accident near Thomas Creek Airport (2U8), Stanley, Idaho. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 flight. The pilot reported that the airplane’s takeoff and climb from Johnson Creek Airport (3U2), Yellow Pine, Idaho, about 30 minutes before the accident, was uneventful. When the airplane reached an altitude of about 10,000 ft mean sea level (msl), the pilot reduced engine power and initiated a descent to 2U8, 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 at the end of the runway. The airplane would not climb, and the pilot maneuvered the airplane through a neighboring canyon, at which time the engine started to regain power. The pilot continued to assess the surrounding terrain and decided that he would not be able to safely turn the airplane around. He then observed a flat area and maneuvered the airplane to that spot to perform a forced landing at the lowest possible airspeed. 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. The closest official weather observation station, located at McCall Municipal Airport, McCall, Idaho, indicated a temperature and a dew point temperature of about 44.5°F and 37.5 F, respectively, about the time of the accident. According to Federal Aviation Administration Special Airworthiness Information Bulletin CE-09-35, Carburetor Icing Prevention, such conditions were conducive to serious carburetor icing at cruise power.