Accident Details
On May 15, 2018, about 0945 eastern daylight time, a Grumman American Aviation Corporation AA-1B airplane, registration N6550L, impacted terrain during a forced landing at the Butler County Regional Airport-Hogan Field (HAO), near Hamilton, Ohio. The accident occurred following a loss of engine power. The private pilot, who was the sole occupant, sustained serious injuries. The airplane received substantial wing and fuselage damage. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a test flight originating from HAO, under day visual meteorological conditions without a flight plan.
Aircraft Information
The airplane was equipped with an engine that had been installed and an annual inspection completed on April 3, 2018, at a tachometer time of 1,427.3 hours. Total airframe time was 4,126 hours, total engine time 6,758.4 hours, and 1.4 hours since the engine's last major overhaul. The airplane had a fuel capacity of 24 gallons. The aircraft carried a J.P. Instruments Engine Data Management (EDM) 350 system, which monitors engine parameters. After the accident, the unit was removed and examined by the NTSB Vehicle Recorder Laboratory. The download contained recordings for six flights, but the data was marked as "BADFLT" with no engine data recorded. The unit stored the amount of fuel available (14.5 gallons) and fuel used (1.5 gallons).
Previous Maintenance and Events
According to the prior owner of the accident airplane, he flew the airplane on April 12, 2018, about 1000, for a maintenance test flight following an engine swap. During a preflight, two blocks of wood were found behind the rudder pedals, which were removed. The airplane then failed a run-up due to engine roughness. A mechanic believed the roughness was caused by oil bypassing new piston rings and fouling the spark plugs. After cleaning and reinstalling the plugs, the engine appeared to run "ok." The prior owner accompanied the mechanic on a test flight. During taxi, the mechanic did not perform an engine run-up before taking the active runway. Takeoff power appeared normal until about 100 ft above ground level, where the engine abruptly lost power. The airplane was put down on the remaining runway, stopping about 30 ft from the end. The mechanic later removed the carburetor and sent it for overhaul. The mechanic reinstalled the overhauled carburetor and conducted the accident flight on May 15, 2018.
Witness and Video Evidence
Witnesses stated that the airplane took off on runway 29; they heard the engine stop, and the pilot attempted to circle back to the airport but did not make it. The airplane impacted terrain left wing low during the forced landing, sustaining substantial damage. A video from a local parking lot camera captured the accident sequence and was appended to the docket.
Pilot Information
The accident pilot held an airframe and powerplant mechanic certificate. He completed an accident report that did not contain a narrative of the accident flight and advised that he did not recall the accident. Additionally, the pilot did not indicate the date of his last flight review.
Weather Conditions
At 0953 on the day of the accident, the recorded weather at HAO was: wind variable at 5 knots, visibility 10 statute miles, sky clear, temperature 26°C, dew point 17°C, altimeter 29.93 inches of mercury. The weather present on the accident day was conducive to moderate carburetor icing at cruise power and serious icing at descent power.
Wreckage Examination
On May 16 and 17, 2018, an FAA aviation safety inspector and an air safety investigator from Lycoming Engines examined the wreckage. The engine produced a thumb compression at all cylinders when the crankshaft was rotated, and the engine was not subsequently disassembled. All bottom spark plugs were coated with oil, consistent with gravity settling oil on them. During the examination, a B-nut fitting on the left fuel tank exhibited discoloration consistent with fuel staining. No preimpact anomalies were found that would have kept the accident engine from operating normally.