Amateur-built MURPHY REBEL N24V accident near Falmouth, Massachusetts

Probable cause

The pilot's delayed application of carburetor heat, which resulted in a loss of engine power.

NTSB analysis

While completing a cross-country flight, with the airplane over a seacoast and descending to pattern altitude, the pilot reduced power. The engine "hesitated" a couple of times, so the pilot increased power and applied full rich mixture. As the engine "caught" and accelerated, the pilot applied carburetor heat. He then leveled the wings and looked at the wing root fuel sight gauges to confirm that the airplane had fuel. At the same time, the engine again began to run rough. The pilot rocked the wings to ensure that there was no air lock in the fuel lines and confirmed that the magnetos were on and the primer was in; however, the engine lost total power, the propeller stopped completely, and the airplane descended into a tree. The airplane was subsequently removed from the tree, fuel was confirmed onboard, and no preexisting mechanical anomalies were noted. The airplane's wings were then removed for its transport to a storage facility. At the facility, an auxiliary fuel tank was placed on top of the cabin, with fuel flow directly to the carburetor. After several attempts, the engine was started, and it eventually ran at all power settings. A carburetor icing probability chart revealed that, at the ambient temperature and dew point at the time of the accident, conditions favored carburetor icing at glide and cruise power. It is likely that, if the pilot had applied carburetor heat before his initial power reduction, it would have prevented the formation of carburetor ice and avoided the loss of engine power.

Text from the NTSB. Open the NTSB docket for ERA12LA279 for the full record.