Incident Overview
A certified flight instructor (CFI) and a student pilot were conducting an instructional flight involving multiple practice takeoffs and landings. Before departure, the instructor did not visually inspect the fuel tanks, though the fuel gauge indicated just below the full mark and the student reported that the tanks were full. Based on his experience with the aircraft, the instructor estimated that the fuel on board would last approximately 4 hours.
Sequence of Events
About 3 hours into the flight, while returning to the home airport, the engine lost power. The instructor attempted to restart the engine but was unsuccessful. He subsequently executed a forced landing to a grass field. During the landing, the right wing struck a tree, causing substantial damage to the wing strut. Additionally, the nose gear separated from the airframe, and both wing tips, the engine cowling, and wheel fairings sustained damage.
Post-Incident Examination
A Federal Aviation Administration (FAA) inspector drained the fuel tanks after the incident. The right wing tank yielded approximately 3/4 of a gallon of fuel, and the left wing tank yielded about 1/2 gallon. The fuel line to the carburetor was removed and found to contain some fuel. The gascolator was removed, yielding approximately 7 to 8 ounces of fuel with no debris present. The carburetor was removed and disassembled; approximately 2 ounces of fuel, also free of debris, was found in the bowl. No mechanical deficiencies were identified with the airframe or engine.
Analysis
The fuel remaining in the aircraft after the incident was insufficient to sustain engine operation. The estimated 4 hours of fuel did not account for the actual consumption during the training maneuvers, which likely included numerous takeoffs and landings. The lack of a visual fuel tank inspection before departure meant reliance on the fuel gauge and the student's statement, which proved inaccurate.