Champion 7BCM N7620B accident near Tyrone, Georgia

Probable cause

A partial loss of engine power during cruise flight for reasons that could not be determined because postaccident examination of the engine revealed no anomalies that would have precluded normal operation.

NTSB analysis

The airline transport pilot was conducting a revenue sightseeing flight with one passenger onboard. During cruise flight, while the airplane was level at 3,000 ft mean sea level, the engine began to lose power. The pilot applied carburetor heat with no improvement; the engine speed remained at 2,000 rpm. He then turned the carburetor heat off and checked the magnetos and noted no significant change in performance. He then reapplied carburetor heat with no improvement; the pilot left the heat on for the remainder of the flight. The airplane would not maintain altitude, so he conducted a forced landing in a grass field. After touchdown, the airplane nosed down in high vegetation, and the main landing gear collapsed. The airplane sustained structural damage to the forward fuselage and engine firewall.

Postaccident examination of the airframe and engine revealed no evidence of preimpact mechanical failures or malfunctions that would have precluded normal operation, and there was sufficient fuel onboard at the time of the accident. Although the weather conditions at the time of the accident were conducive to serious carburetor icing at glide power, the pilot applied carburetor heat twice, which should have melted any existing ice, but power was not restored. Therefore, the investigation could not determine the reason for the partial loss of engine power.

Text from the NTSB. Open the NTSB docket for ERA16LA172 for the full record.