N24GL

HISTORY OF FLIGHTOn November 24, 2019, about 0940 central standard time, an experimental amateur-built Bushby Mustang II airplane, N24GL, was substantially damaged when it was involved in an accident near Milton, Florida. The pilot was fatally injured. The airplane was operating as a Title 14 Code of Federal Regulations (CFR)Part 91 personal flight.

Two witnesses were driving on airport property when they saw the airplane do a touch-and-go maneuver on runway 36. They both momentarily turned their attention away, but, when they looked back at the airplane, it was descending straight down to the ground from a height of about 50-100 ft just past the north end of the runway. Neither one heard the airplane's engine prior to impact because the windows of the car were rolled up. The couple immediately drove to where the airplane impacted the ground and called 911. One witness said that when he arrived, he did not see any leaking fuel but turned the fuel selector from the ON position to the OFF position because there was a strong odor of fuel.

Two flight instructors were on the tarmac watching their students, who were soloing in the traffic pattern. One of the instructors only saw the accident airplane when it was on final and did not see the accident. The other instructor first saw the accident airplane parked in the run-up area for runway 36. He said the airplane stayed in the run-up area for quite a while. The instructor then turned his attention to his student who had departed runway 36 and was in the traffic pattern. The next time the instructor observed the accident airplane, he said it was departing, but he was not sure if this was his initial takeoff or not. He said the airplane used almost the entire length of the 3,701-foot-long runway. When it rotated, the airplane was "pitching up fairly aggressively" and he could see the entire top of the airplane. The airplane stalled and entered a spin. The airplane spun to the left a quarter of a rotation "where the plane was completely vertical upon impact with the ground." The instructor did not recall hearing the airplane’s engine. He said that 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 that is what he thought the accident pilot was doing.

A witness, who co-owns a flight school at the airport and lives about 1 mile off the end of runway 36, was at home on the morning of the accident. He said he heard two airplanes in the traffic pattern, along with a third airplane whose engine sounded “muted”, “odd,” and “not making full power.” The witness said the engine then went quiet. When he could not hear it anymore, he thought something must have happened to the airplane.

A friend of the pilot said about 3 weeks before the accident the pilot told him that he had to reject a takeoff due to loss of engine power, but never said what caused the power loss. The pilot had told him he was having problems with the electronic magnetos, but never mentioned anything about water in the fuel system.

PERSONNEL INFORMATIONThe pilot, who was an active-duty flight officer, who primarily flew large or medium size, multiengine propeller (mobility) aircraft in the United States Air Force (USAF), held a Federal Aviation Administration (FAA) airline transport pilot certificate with ratings for airplane single and multiengine land.

There was no endorsement for a flight review in the pilot's civilian logbook as required by 14 CFR 61.56.; however, the regulation allowed a pilot to have a proficiency check conducted by a US armed force for an operating privilege in the previous 24 months, to count as a flight review. According to a USAF representative, "...as of 24 Nov 2019, [the pilot] met all required flying currency and qualification standards appropriate for his position as a senior US Air Force pilot."

WRECKAGE AND IMPACT INFORMATIONThe airplane came to rest on its nose in the grassy area located off the departure end of runway 36 on a magnetic heading of about 133°. The tail section of the airplane was straight up in the air and there was no post-impact fire. All major flight controls were accounted for at the scene and the single flap was fully retracted.

The canopy was found separated from the airframe and was resting to the left of the airplane. The forward section of the empennage was deformed, and the tail section was bent to the right. The leading edge of the right and left wings exhibited leading-edge impact damage. The tail section appeared undamaged.

The cockpit area sustained impact damage, but both the pilot and co-pilot seats remained attached to their respective seat-rails. According to a witness, the pilot ejected from the airplane on impact. The airplane was equipped with a 4-point restraint system. The pilot's shoulder harness was not attached to the inertial reel or the lap belt. The shoulder harness section was found on the floorboard of the co-pilot's seat. The shoulder harness was tested by buckling it into the inertial reel attach point. The buckled worked as designed. The lap belt was found buckled but it had separated from its inboard structural attach point. The outboard attach point was still secure to the airframe.

Flight control continuity was established for the ailerons and rudder by movement of the flight controls. The elevator did not move when the flight controls were moved. Further examination revealed that that the elevator control tube was still attached to the flight controls but was fractured on the forward and aft end where it connected to a bell crank mid-cabin. The fractured rod ends of the elevator control tube were examined at the NTSB Materials Laboratory. The examination revealed the rods ends failed due to ductile overstress from impact. The elevator trim was intact and smoothly moved through its full range when tested.

The engine was pushed aft into the main fuel tank and instrument panel. The main fuel tank, the fuel lines from the fuel selector to the tank, and the firewall fuel strainer bowl were breached. Each auxiliary fuel tank (located in the wing root of each wing) appeared intact. No fuel was found in the right auxiliary tank and about a half-gallon of 100LL aviation gas was drained from the left auxiliary tank. The fuel was absent of debris and water.

The throttle, mixture and propeller controls sustained impact damage. The primer was “in and locked” and the carburetor heat was in the “off” position.

The two-bladed propeller remained attached to the engine. One blade was bent aft at mid-span and exhibited leading edge polishing and chordwise scratching along the entire span of the blade. The other blade appeared undamaged. The propeller and crankshaft flange were removed to facilitate rotation of the engine, which was accomplished via the vacuum pump port. Compression and valve train continuity were established on all four cylinders. A lighted borescope was used to examine each cylinder and no anomalies were noted to the pistons and valves. The oil filler neck was found cracked but the dip stick remained inside the filler neck. The oil suction screen was removed and absent of debris.

The carburetor separated from the oil sump and only the carburetor mating flange remained attached to the sump. The carburetor was disassembled and about a tablespoon of clear and rust-colored fluid and corrosion were observed in the bowl and the accelerator pump chamber. The fluid was tested for water using a water finding paste, and all tests were positive for water. A milky white fluid was found in the fuel inlet screen port and it also tested positive for water. The fuel inlet screen was removed from the carburetor and was absent of debris. The firewall fuel filter bowl was breached during impact, but its screen was in the wreckage. The screen was coated with a white powdery residue.

A review of the airframe logbook revealed that the main (header) fuel tank was cleaned and drained at the last condition inspection. According to the mechanic that performed the inspection, he said he cleaned the tank because he had drained half of a water bottle's worth of water from the fuel tank. The water looked like "rainwater" with very "light" sediment. The mechanic drained and dried the tank before adding new fuel to perform the post-maintenance engine run. He did not know how water got into the fuel system and he did not inspect the carburetor for water at the time he cleaned the main fuel tank.

The engine was equipped with dual electronic magnetos and eight automotive spark plugs. The pilot told the same mechanic that he had experienced a larger than normal RPM drop on the left magneto during an engine run just days before the accident. The mechanic said he removed, cleaned, and rotated all eight sparkplugs. The pilot re-tested the engine and a larger than normal RPM drop was observed on the right magneto. The mechanic said that he and the pilot agreed there was an issue with the spark plugs, so the pilot went to a local automotive shop and purchased a new set of plugs. The mechanic installed the new plugs the day before the accident, and the pilot performed another test run of the engine. According to the mechanic, the pilot said both magnetos tested normally, and that he planned to take the airplane up for a test flight but would perform a long test-run of the engine before he departed. The mechanic did not know if the pilot did an engine test run that day but knew that the pilot did not fly due to weather.

Postaccident examination of the magnetos revealed they were secured to the engine with some minor impact damage. The No. 1, No. 2 and No. 3 top spark plugs exhibited some impact damage. All spark plugs were removed and appeared new with no damaged electrodes. Both magnetos were tested at the manufacturer under NTSB supervision. No mechanical or functional anomalies were noted with either magneto.

The airplane was equipped with a Gr...