Accident Details
On August 5, 2020, at approximately 1333 eastern daylight time, a Piper PA-25-235, registration N223AB, was substantially damaged in an accident near Miami, Florida. The pilot, the sole occupant, was not injured. The aircraft was being operated as a Title 14 Code of Federal Regulations Part 91 banner tow flight.
Flight Narrative
After picking up a banner, the pilot climbed on an easterly heading to an altitude of 1,300 ft mean sea level (msl). He leaned the mixture and then applied carburetor heat for 15 to 30 seconds at the top of the climb, noting a 100-rpm drop. Removing the carburetor heat, he flew southeast, then turned south. While over the Port of Miami at 1,100 ft msl, he checked the carburetor heat a second time, again applying it for 15 to 30 seconds and observing a 100-rpm drop. He then removed it and continued south.
South of Fisher Island, the pilot made a radio call on the Watson Island Advisory frequency, stating the flight was at 1,100 ft msl, turning north, and descending to 700 ft msl. He applied carburetor heat before descending, but before adjusting the throttle, the engine rpm dropped to between 1,000 and 1,200.
Maneuvering over water, the pilot dropped the banner. With full power applied, mixture leaned, and carburetor heat on, he felt the engine was not producing power. He selected a landing site, checked the magnetos, set the mixture to full rich, and with carburetor heat still applied, descended to between 50 and 100 ft. At that point, the engine sputtered "like it wanted to come back" but did not recover. Just before touchdown, he pulled the throttle and mixture controls and was fast at the intended site. The aircraft touched down and collided with a fence. The pilot reported the engine was stopped when he came to rest, and he secured the aircraft.
Post-Accident Examination
An FAA inspector examined the aircraft at the accident site. No fuel contamination was found in the fuel tank or airframe fuel strainer. The propeller blades had only scratches, though the propeller spinner was damaged. In the presence of the inspector and pilot, a company employee started the engine and briefly ran it at idle. After recovery, an inspection of the carburetor heat system revealed no discrepancies. The engine was operated using the fuel that was in the tank at the time of the accident.
Weather Conditions
At 1353, the weather reported at Miami International Airport (MIA), about 8 miles west-northwest of the accident site, included a temperature of 28°C and a dew point of 25°C. The calculated relative humidity was about 80%. Review of the icing probability chart in FAA Special Airworthiness Information Bulletin CE-09-35 indicated that the atmospheric conditions were "conducive to icing at glide [idle] and cruise power."