Accident Details
On March 26, 2016, at approximately 1115 central daylight time, a Grumman American Aviation Corp. AA-1B airplane, registration N8883L, impacted terrain during a forced landing near Stephenville, Texas, following a loss of engine power. The pilot and his passenger sustained serious injuries, and the airplane was substantially damaged.
The airplane was operated as a personal flight under 14 Code of Federal Regulations Part 91. Day visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The flight originated from Dallas Executive Airport (RBD) near Dallas, Texas, at about 0958, destined for Stephenville Clark Regional Airport (SEP) near Stephenville, Texas.
Pilot Information
The pilot held a Federal Aviation Administration (FAA) private pilot certificate with an airplane single-engine land rating and a third-class medical certificate issued in January 2016. He reported 131.9 total flight hours, including 14.1 hours in the accident airplane model.
Aircraft Information
N8883L was a 1974 Grumman American Aviation Corp. AA-1B, a low-wing, fixed-tricycle landing gear, two-place monoplane (serial number AA1B-0383). It was powered by a 108-horsepower Lycoming O-235-C2C engine (serial number L-11776-15). The fuel system comprised a tubular main wing spar with two fuel cells, each holding 12 gallons (11 usable). Fuel quantity was indicated by vertical sight gauges on the cabin walls. According to fueling records, the airplane was serviced with 4.02 gallons of 100 low-lead aviation gasoline on March 24, 2016.
Sequence of Events
According to the pilot's report, a full preflight including a fuel check was completed. After departing RBD, the flight proceeded toward SEP. Approximately 18 miles from the airport, while at 4,500 feet mean sea level with the left wing fuel tank selected, the engine lost power. The pilot performed emergency procedures, turned on the auxiliary fuel pump, selected the right fuel tank, and successfully restarted the engine. He then descended 300 feet at full power to regain airspeed. About four miles east of the airport, the engine lost power again. The pilot attempted restarts without success and prepared for an off-field landing on Highway 377 but encountered oncoming traffic. He selected an open field, leveled the wings, and maintained airspeed. The airplane struck the top of a horse trailer, and the pilot was ejected. Both occupants were transported to a hospital.
Investigation Findings
Examination of the wreckage by FAA, engine manufacturer, and NTSB inspectors revealed no anomalies that would have precluded normal engine operation. The carburetor bowl contained a liquid with debris that was later identified as avgas. The electric fuel pump screen and cap contained debris. Spectroscopic analysis of the debris showed similarities to surfactants common in aviation fuel, and X-ray fluorescence indicated metals typically found in aircraft fuel systems.
A GoPro camera recovered from the wreckage recorded the flight. The video showed the pilot's fuel management, including tank switching and fuel pump use. At about 1104, the fuel pressure dropped near zero before the pilot switched tanks and turned on the fuel pump, restoring pressure. At about 1111, the fuel pressure again dropped to near zero, and the engine lost power. During the descent, the pilot could be heard stating that the airplane was new to him and that he "just run it out of fuel."
Weather Conditions
At 1115, weather recorded at SEP included wind from 190 degrees at 8 knots, visibility 10 statute miles, clear sky, temperature 18°C, dew point 9°C, and altimeter 29.95 inches of mercury.