Gulfstream American Corp AA-5A N26889 accident near Crossville, Tennessee

Probable cause

A partial loss of engine power due to carburetor icing, which resulted in a descent and impact with terrain. Contributing to the accident was the pilot’s failure to apply carburetor heat following the initial loss of engine power.

NTSB analysis

The student pilot was on a multi-leg, solo cross-country flight in atmospheric conditions conducive to serious carburetor icing at descent power. Track data and interviews with the pilot’s instructor revealed that the airplane entered a gradual descent over a 5-minute span that included a 450° descending right turn. Shortly thereafter, the pilot called his instructor via cell phone and reported that the airplane’s engine was producing only partial power. The instructor stated that the pilot’s demeanor was calm, and as such, the discussion felt conversational and that there was time to discuss fuel state, engine control positions, landing at the nearest airport, or selecting a forced landing site.

When asked, the pilot reported he was “40 to 50 miles” from his departure airport; however, track data revealed that the airplane was about 8 miles south of the departure airport. The instructor suggested the pilot make an “emergency landing in a field,” but the pilot reported that there were trees and mountains ahead of him before the sounds of impact were heard.

The airplane was consumed by postcrash fire. Control continuity to all flight control surfaces was confirmed; examination of the engine revealed the accessories were destroyed by fire and that the core exhibited no preimpact anomalies. The fracture surfaces on a separated carburetor heat control revealed signatures consistent with overstress due to impact and high temperatures.

Based on the lack of mechanical anomalies and the partial loss of engine power as reported by the pilot, it is likely that the engine lost partial power as the result of carburetor ice accumulation, which resulted in descent into terrain. It is likely that the pilot’s prompt application and use of carburetor heat in accordance with the airplane’s operating handbook would have restored engine power.

Text from the NTSB. Open the NTSB docket for ERA21FA232 for the full record.