Cessna 180J N180LP accident near Gaylord, Michigan

Probable cause

The pilot's failure to use carburetor heat while operating in weather conditions that were conducive to carburetor ice formation, which resulted in a total loss of engine power due to carburetor ice accumulation.

NTSB analysis

The private pilot was flying the airplane at a low altitude when the engine lost total power. The pilot reported that the engine did not sputter, bang, or run roughly before the loss of engine power; however, several witnesses heard the airplane's engine running roughly immediately before the crash. One witness reported that the airplane's engine fluctuated between "sputtering" and "revving" before it lost total power. The airplane collided with trees and terrain during the subsequent forced landing and came to rest inverted.

Postaccident examination of the airplane and engine did not reveal any evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation. Additionally, the airplane had ample fuel available that did not contain any water or debris. The engine also demonstrated the ability to produce rated horsepower during a postaccident operational test run. The carburetor heat control was in the "OFF" position.

The weather conditions at the time of the accident were conducive to moderate carburetor icing at cruise power and serious carburetor icing at descent power. The pilot reported that he did not use carburetor heat during the flight because he was operating the engine at a cruise power setting. The airplane flight manual states that carburetor heat should be used upon a loss of engine power or an unexplained decrease of manifold pressure, a roughly running engine, or before the throttle is moved to idle for landing. Additionally, the use of carburetor heat might be required to avoid carburetor ice accumulation during a descent at a reduced engine power setting. According to a Federal Aviation Administration Special Airworthiness Information Bulletin, pilots should use carburetor heat while in weather conditions where carburetor icing is probable. Based on the available information, the total loss of engine power was likely due to carburetor ice accumulation. Additionally, the low altitude at which the loss of engine power occurred precluded the pilot from reestablishing normal engine operation before the airplane descended into trees.

Text from the NTSB. Open the NTSB docket for CEN17FA332 for the full record.