Accident Overview
On May 5, 2023, at about 0745 eastern daylight time, an Aeronca 7DC-CONV, registration N3058E, was substantially damaged during an accident near Fort Mill, South Carolina. The airplane was operated under Title 14 Code of Federal Regulations Part 91 as a personal flight. The private pilot and pilot-rated passenger were not injured.
Pilot Account
The pilot provided a written statement and was interviewed by a Federal Aviation Administration (FAA) aviation safety inspector. He reported a normal preflight inspection, engine start, run-up, taxi, departure, and climb to about 2,000 ft mean sea level, where he established heading toward his planned destination. Due to radio and airplane traffic at the destination airport, he amended his destination and decided to descend and follow a river toward another airport.
After descending about 1,000 ft, he leveled the airplane and applied power, but there was no thrust. He adjusted the throttle, mixture, pulled the carburetor heat, and cycled the magnetos without any change in engine speed. The engine continued to run at 1,000 rpm.
Forced Landing
The pilot initially selected an open area of fields and golf courses for the forced landing, but decided to land in the river when he determined the airplane would not reach the open area. The airplane touched down in shallow water, nosed over, and came to rest inverted. The pilot and passenger egressed without injury.
Post-Accident Examination
Examination at the site revealed damage to the rudder, wing attachment points, and their associated attachment bolts. Control continuity was established from the flight controls to all flight control surfaces.
The airplane was recovered to the operator’s facility and prepared for an engine test run. The impact-damaged propeller was removed and a propeller of the same make and model was installed. Spark plugs were removed, water drained from cylinders, and plugs were dried, cleared of debris, and reinstalled. Magneto timing was confirmed; magnetos were removed, dried, and reinstalled in their as-found positions.
The fuel line between the fuel selector valve and the firewall was fractured due to overstress, so a fuel container was plumbed into the carburetor for the test run. A fresh battery was installed, and the starter was excited using battery power. The engine started with fuel plumbed through the primer port of the carburetor, idled and accelerated smoothly, and ran continuously until stopped using the mixture control. During the run, a magneto check and carburetor heat control check were performed satisfactorily at 1,700 rpm.
The engine was then restarted with fuel supplied through the main fuel supply port, and the tests were repeated satisfactorily. The engine was accelerated into the "green arc" before being stopped again using the mixture control.
Atmospheric Conditions
According to the carburetor icing probability chart contained in FAA Special Airworthiness Information Bulletin (SAIB) CE-09-35, Carburetor Icing Prevention, the atmospheric conditions reported by the pilot at the point of departure and those recorded at a station about 10 miles west of the accident site were conducive to the development of carburetor icing at glide and cruise power.
In both his interview and written statement, the pilot stated that he applied carburetor heat only after detecting the loss of engine power.