Accident Overview
On November 24, 2019, at about 0940 central standard time, an experimental amateur-built Bushby Mustang II airplane, registration N24GL, was substantially damaged when it crashed near Milton, Florida. The pilot, who was the sole occupant, sustained fatal injuries. The flight was conducted as a Title 14 Code of Federal Regulations Part 91 personal flight.
Witness Accounts
Two witnesses driving on airport property observed the airplane performing a touch-and-go maneuver on runway 36. After momentarily looking away, they saw the airplane descending straight down from about 50-100 ft just past the north end of the runway. They did not hear the engine due to having their car windows up. They drove to the impact site and called 911. One witness turned the fuel selector from ON to OFF due to a strong fuel odor.
Two flight instructors were on the tarmac. One saw the accident airplane only on final and did not witness the crash. The other noted the airplane remained in the run-up area for a while, then departed using almost the entire 3,701-foot runway. After rotation, the airplane pitched up aggressively, stalled, and entered a spin, rotating a quarter turn left before impacting vertically. This instructor did not hear the engine.
A witness about 1 mile off the end of runway 36 heard two airplanes in the traffic pattern plus a third with a “muted,” “odd” engine sound that later went quiet. He suspected something had happened.
A friend of the pilot reported that about three weeks before the accident, the pilot had aborted a takeoff due to engine power loss and mentioned problems with the electronic magnetos, but not water in the fuel.
Pilot Information
The pilot was an active-duty United States Air Force flight officer who primarily flew large or medium multiengine propeller aircraft. He held an FAA airline transport pilot certificate with single- and multiengine land ratings. Although his civilian logbook lacked a flight review endorsement, a USAF representative confirmed he met all required flying currency and qualification standards for his position as of the accident date.
Wreckage Examination
The airplane came to rest on its nose in a grassy area off the departure end of runway 36, oriented on a magnetic heading of about 133°. The tail was vertical and there was no post-impact fire. The canopy separated and was found left of the airplane. The forward empennage was deformed, the tail section bent right. Both wings had leading-edge impact damage. Flight control continuity was confirmed for ailerons and rudder; the elevator control tube was fractured at both ends of a mid-cabin bell crank, and fractography revealed ductile overstress from impact. The elevator trim functioned normally.
The cockpit sustained impact damage; both seats remained attached. The pilot’s shoulder harness was not attached to the inertial reel or lap belt, and the lap belt had separated from its inboard attach point. The engine was displaced aft, breaching the main fuel tank, fuel lines, and firewall fuel strainer bowl. The auxiliary fuel tanks were intact; the right tank had no fuel, while the left tank contained about half a gallon of 100LL aviation gasoline free of debris and water.
Engine and Fuel System Examination
The two-bladed propeller remained attached; one blade was bent aft with polishing and chordwise scratching, the other undamaged. Engine rotation via the vacuum pump port confirmed compression and valve train continuity on all four cylinders. Borescope inspection revealed no anomalies. The oil suction screen was clean.
The carburetor separated from the oil sump; only the mating flange remained. Disassembly revealed about a tablespoon of clear and rust-colored fluid and corrosion in the bowl and accelerator pump chamber, which tested positive for water. Milky white fluid in the fuel inlet screen port also tested positive for water. The firewall fuel filter screen was coated with a white powdery residue.
The airframe logbook indicated the main fuel tank was cleaned and drained during the last condition inspection due to about half a water bottle's worth of water found. The mechanic did not inspect the carburetor for water at that time. Postaccident examination of the dual electronic magnetos showed no mechanical or functional anomalies. The pilot had reported a larger-than-normal RPM drop on the left magneto days before; spark plugs were replaced, and a test run indicated normal operation. The pilot planned a test flight but did not fly due to weather the day before the accident.
No useful data was recovered from the Grand Rapids Technology EFIS and EIS units due to impact damage. Toxicology testing identified diphenhydramine in the pilot’s blood and urine.