Piper PA25 N223AB accident near Miami, Florida

Probable cause

A total loss of engine power due to carburetor ice that was not detected by the pilot.

NTSB analysis

The commercial pilot departed on a banner tow flight and after takeoff, as part of his procedures, briefly checked two times for carburetor ice. Prior to beginning a descent, he applied carburetor heat a third time, but before he had time to adjust the throttle, the engine lost total power. Unable to restore power he maneuvered over water and dropped the banner as to avoid injury to any persons or property then maneuvered for a forced landing on a road. After touchdown on the road, the airplane collided with a fence and went down a slight embankment before coming to rest upright.

Postaccident examination and operational test run of the engine, as well as the carburetor heat system, revealed no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation.

The weather conditions at the time of the accident were conducive to the formation of carburetor icing at glide (idle) and cruise engine power settings. Thus, it is likely that during cruise flight before the third application of carburetor heat, carburetor ice formed that was not detected by the pilot.

Text from the NTSB. Open the NTSB docket for ERA20LA275 for the full record.