Incident Details
A aircraft modified for banner towing was being used for that purpose. After approximately 3 hours and 20 minutes of flight time, the pilot took off for a fourth banner towing flight. The pilot reported using the fuel gauges to estimate the amount of fuel remaining, concluding that 5 or more gallons were onboard prior to the last takeoff.
During the flight, the pilot flew to a stadium and executed 6 to 8 turns. While heading back to the airport, the engine lost power. Following the power loss, the pilot reportedly maintained an airspeed of 60 mph. The aircraft's owner's manual recommended a minimum speed of 65 mph for attempting an engine restart.
Pilot's Actions
After the power loss, the pilot released the banner just before ditching the aircraft in a river. The aircraft was subsequently towed to the riverbank by a boat and recovered later.
Recovery and Examination
Approximately 2 gallons of fuel were found remaining in the fuel tanks. No preimpact or mechanical failures were discovered during the examination of the aircraft.