Beech C23 N2120W accident near Machias, Maine

Probable cause

The pilot's delay in applying carburetor heat, which resulted in a total loss of engine power due to carburetor icing.

NTSB analysis

The private pilot descended the airplane to the destination airport but did not apply carburetor heat. While in the traffic pattern, as the airplane was turning onto a left base leg for the runway, the engine began to run roughly. The pilot then applied carburetor heat, but the engine lost total power. After realizing that the airplane was not going to glide to the runway threshold, the pilot performed a forced landing in a grassy area just short of the runway. During the landing, the nose gear collapsed and the airplane spun 180° before it came to rest, which resulted in substantial damage to the right wing.

Examination of the wreckage did not reveal any evidence of preimpact mechanical malfunctions or failures of the ignition system, fuel system, or engine that would have precluded normal operation. The weather conditions at the time of the accident were conducive to the formation of serious carburetor icing at glide power. Although the Descent checklist in the pilot operating handbook for the airplane make and model instructed the pilot to use carburetor heat as required, the pilot did not apply carburetor heat before initiating the descent; rather, he waited until the engine began to run roughly. It is likely that the engine initially lost partial power after developing carburetor ice and that the pilot's delayed application of carburetor heat was ineffective at melting any accumulated ice.

Text from the NTSB. Open the NTSB docket for ERA17LA325 for the full record.