What happened
Prior to departure, the instructor preflighted the aircraft and used a calibrated stick to verify fuel levels, finding 8 gallons in one tank and 7 gallons in the other. The aircraft departed and was cruising at 2,700 feet for approximately one hour when the instructor reported a loss of all or most engine power. During the event, the engine backfired four or five times, and the crew was unable to restore power.
The instructor executed a forced landing into a parking lot, during which the aircraft's left wing struck a light pole.
The investigation
An inspection of the aircraft by a Federal Aviation Administration Inspector showed that one wing fuel tank had been ripped open. However, investigators found that neither wing tank contained fuel at the time of the inspection, and there was no odor of fuel present on the ground.
Records regarding refueling indicated that the aircraft had been refueled to a total of 20 gallons approximately 8/10 hours prior to the accident flight. The engine's average fuel consumption was noted at 6.8 gallons per hour. Additionally, a carburetor icing probability chart indicated that atmospheric conditions during the flight were conducive to serious icing at cruise power.