ERA20FA043 · Bushby BUSHBY MUSTANG M II

Witnesses observed the pilot of the experimental, amateur-built airplane perform a touch-and-go-landing on the 3,701-foot-long runway before it pitched up “fairly aggressively" and entered a near vertical climb to about 50 ft. The airplane then stalled and entered a spin toward the ground. None of these witnesses heard the airplane’s engine prior to impact. The pilot told a friend that he had to reject a takeoff about 3 weeks prior due to a loss of engine power, but the pilot never said what caused the engine to lose power. The pilot did state that he was having issues with the electronic magnetos. A mechanic had replaced all eight automotive spark plugs 2 days before the accident due to an excessive rpm drop on each electronic magneto. A post-maintenance test run of the engine revealed that replacing the spark plugs rectified the problem. The pilot told the mechanic that he would do an extensive engine run-up before he flew the airplane, which he did (per a witness) on the morning of the accident. A postaccident examination of the engine, including both magnetos and the spark plugs, revealed no mechanical deficiencies that would have contributed to a loss of engine power. Examination of the fuel system revealed a small amount of water and corrosion in the carburetor bowl, the accelerator pump chamber, and the fuel inlet screen port. Maintenance records revealed that a mechanic had drained the main fuel tank at the last inspection due to water in the tank. The mechanic said he dried the tank and added fresh fuel but did not check the carburetor for water. A witness said it was not unusual to see pilots flying their sport airplanes low and level over the runway before making a steep climb near the end of the runway, and this is what he thought the pilot was doing. The airplane stalled and spun to the ground from a height of about 50 ft, which was too low for the pilot to recover. It is possible that the engine experienced a loss of power due to fuel contamination, but the pilot’s actions were not consistent with a power loss prior to him pulling the airplane into a climb. Since no mechanical anomalies were observed with the airplane’s flight control system that would have precluded normal operation, the pilot failed to maintain a proper angle of attack and airspeed on takeoff, which resulted in an aerodynamic stall at an altitude that was too low for him to recover. Diphenhydramine was detected in the pilot’s blood and urine; however, the levels were not sufficient to contribute to the accident.

Verbatim NTSB analysis and probable cause from the NTSB dataset