On December 27, 1995, a Cessna 152 (registration N53321) was involved in an aviation accident near Long Beach, CA. Investigators recorded the probable cause as: The pilot's failure to apply carburetor heat in conditions conducive to icing, which resulted in engine power loss. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 8 related events involving the same aircraft type or operator are linked below.
Engine RPM dropped to flight idle during a descent over water. The pilot applied carburetor heat but could not restore power, resulting in a controlled ditching.
What happened
The aircraft was engaged in an over-water flight phase when the engine experienced a sudden loss of power. During the descent, the engine revolutions per minute (RPM) decreased to the flight idle setting. The pilot attempted to diagnose the issue by checking the fuel mixture and the fuel selector switch, but these actions did not resolve the problem. Unable to restore engine power, the pilot executed a controlled ditching of the aircraft into the water.
Findings
Post-accident examination revealed that the carburetor heat control handle and valve were in the off (cold) position. Review of the icing probability graph indicated that the aircraft was operating in atmospheric conditions conducive to carburetor icing. The lack of applied carburetor heat likely allowed ice accumulation, which restricted fuel-air flow and caused the engine to lose power.
Probable cause
The pilot's failure to apply carburetor heat in conditions conducive to icing, which resulted in engine power loss.