The pilot reported that, while in cruise flight at about 4,000 feet MSL, he advanced the throttle to initiate a climb, but the engine began to lose power. In an effort to regain power, he further advanced the throttle and propeller levers and switched the fuel selector to the left tank to no avail.
He made a forced landing in a small gully near Soldotna, Alaska, which resulted in substantial damage to the wings and fuselage.
The pilot sustained serious injuries in the crash, while a passenger was uninjured.
A Global Data Assimilation System (GDAS) model sounding was created for the accident time and location, with the modeled surface elevation about 2,415 feet MSL. When the data was interpolated for an elevation of 4,000 feet MSL, the data indicated the temperature was about 4.9°C (40.8°F) and the dewpoint was about 1.6°C (34.9°F), with a relative humidity of about 79%.
Based on the carburetor icing probability chart, these conditions would result in “serious icing — cruise power.”
When the pilot was asked if he applied carburetor heat after the loss of power, he stated that he did not, as there was no visible moisture in the area, and he thought carburetor ice would be unlikely.
A Lycoming Service Instruction states, in part: “Flight Operation – During normal flight, leave the carburetor air heat control in the full cold position. On damp, cloudy, foggy or hazy days, regardless of the outside air temperature, be alert for loss of power. This will be evidenced by an unaccountable loss in manifold pressure or RPM or both, depending on whether a constant speed or fixed pitch propeller is installed on the aircraft. If this happens, apply full carburetor air heat, and open the throttle to limiting manifold pressure and RPM.”
Probable Cause: A total loss of engine power due to carburetor icing, which resulted from the pilot’s failure to use carburetor heat while operating in conditions conducive to the formation of carburetor ice.
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This July 2022 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
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