History of Flight
On May 1, 2018, at 1931 Pacific daylight time, an experimental, amateur-built American Air Racing (AAR) Thunder Mustang (Blue Thunder II), registration N352BT, sustained substantial damage during a forced landing at Reno/Stead Airport (RTS), Reno, Nevada. The airline transport pilot was fatally injured. The airplane was registered to TM-1 Ltd. and operated as a Title 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight, which departed about 1815.
The airplane was taking part in an in-flight photography mission with another Thunder Mustang and a Beechcraft Bonanza. This was the second such flight that day. About 1 hour into the accident flight, the group decided to end the mission due to fatigue.
When the airplanes were about 5 miles from the airport, the accident pilot transmitted a "mayday" call. He stated his intention to land on runway 14. The other Thunder Mustang pilot observed the airplane descend, overshoot the runway centerline, then turn wide and realign. The airplane was low and fast over the runway. As it approached the end of the runway, it veered off the right side and nosed over, coming to rest inverted about 20 ft right of the runway edge and 80 ft short of the paved end. The runway showed intermittent black tire skid marks and propeller gouges over 1,200 ft.
A security camera captured the final moments, showing the airplane with main gear on the runway, the tail rising, and then transitioning to a 45° nose-down attitude before exiting the field of view. The main wreckage was found about 50 ft beyond.
Rescue personnel arrived within minutes. The vertical stabilizer was folded against the right horizontal stabilizer; the canopy was shattered. The flaps were found at 43° (full down) and the landing gear extended. The pilot remained in his seat, but was unresponsive. Extraction took about 45 minutes.
Pilot Information
The 80-year-old pilot held an airline transport pilot certificate with multiple type ratings, commercial privileges for single-engine land, and an airframe and powerplant certificate. He was the sole owner of AAR and performed most work on the accident airplane. He reported 30,000 total civilian flight hours as of his last FAA medical exam in July 2017. No logbooks were recovered. His most recent flight experience, from a March 2018 air race application, showed 326 total hours in the accident make and model (287 in the accident airplane) and 34 hours in the previous 90 days. He also flew a Piper PA-34, which had accumulated 5.4 hours in the prior 3 months; the accident airplane had 2.48 hours in that period.
Acquaintances noted he seemed his usual self before the accident, though he needed assistance entering the airplane. One pilot remarked that the accident pilot did not appear to fly with his usual precision on the photography flights. Two days before the accident, a friend saw the pilot struggle with balance and become dizzy after leaning over; he fell and had trouble standing and walking briefly.
Aircraft Information
The airplane was a kit-built, 3/4-scale replica of the P-51 Mustang, made of composite materials. It was powered by a liquid-cooled, fuel-injected 12-cylinder engine (Ryan Falconer Racing Engines) based on a Chevrolet small block. Engine accessories were driven by Kevlar serpentine belts. The propeller was a 101.5-inch, three-blade, hydraulically operated constant-speed Hartzell, with a 60° mechanical high pitch stop for overspeed prevention. It did not have full feathering. The aircraft had retractable landing gear and electrically controlled flaps.
Two Falconer engines were owned: serial number 12022 (accident engine) and 12023 (race engine). The accident engine was overhauled on March 18, 2016, and reinstalled on April 2, 2016. It suffered an overheating event shortly after, was repaired, and reinstalled on March 17, 2017. The last condition inspection was on March 14, 2018, at 17.15 hours since major overhaul (2.48 flight hours before the accident). The flight manual stated that a three-point landing required 2,000 ft of runway, and a wheel landing required 3,500 ft. The stall speed in landing configuration (VSo) was 82 knots.
Meteorological Information
At 1935, the automated observation at RTS reported a direct tailwind for runway 14 at 4 knots, visibility 10 miles, temperature 4°C, dew point 1°C, and altimeter 29.91 inHg.
Flight Recorder Data
The airplane had a customized data recording system (51Aero) that captured engine parameters and GPS location throughout the flight. During the north-south passes, engine speed was about 4,050 rpm with manifold pressure 10-13 inHg. At 1928, while 4 miles north-northwest of the approach end of runway 14 at a GPS altitude of 8,460 ft (about 2,800 ft above terrain), the oil pressure dropped from 72 psi to 0. The auxiliary alternator current dropped to 0, and the battery current increased to 9.6 amps. Engine speed dropped to about 2,000 rpm, and the airplane began to descend.
Over the next 130 seconds, the airplane performed an S-turn descent. Exhaust gas temperatures decreased to about 1,000°F. It arrived about 200 ft above the runway, 2,400 ft beyond the threshold, at 139 KIAS. The airplane touched down at 111 KIAS near the runway midpoint, decelerated, then drifted right with 350 ft of runway remaining. It departed the right side of the runway at 20 KIAS and nosed over.
Data from the previous flight indicated a touchdown speed of about 100 KIAS and a ground roll of about 4,600 ft.
Medical and Pathological Information
In the 11 years before his last FAA medical exam, the pilot reported hypertension, glucose intolerance, knee replacement, and back surgery for nerve compression. He was left with permanent left ankle weakness requiring a brace, and was subsequently certified with a special issuance medical certificate. In 2012, he received a Statement of Demonstrated Ability after a medical flight test. In 2013, he underwent repeat spinal nerve decompression; his foot drop remained. He continued with special issuance until 2016, when the FAA determined it was no longer necessary. At his most recent exam, he was using lisinopril and hydrochlorothiazide for blood pressure, and was issued a second-class medical certificate with a requirement for near-vision glasses.
The autopsy determined the cause of death as positional/traumatic asphyxia. Moderate coronary artery disease (up to 50% stenoses) was noted but otherwise unremarkable. Toxicology testing identified hydrocodone and its metabolites (hydromorphone and dihydrocodeine) in urine, and tramadol and its metabolite in urine, but not in peripheral blood. Both are opioid pain medications considered impairing.
Tests and Research
Postaccident examination revealed that the coolant pump pulley had separated from the pump drive flange. The pulley mounting cap screw heads had detached, leaving threaded studs in the flange. Both serpentine belts and the top of the engine coolant outlet hose had also detached. The NTSB Materials Laboratory examined the components. The pulley and flange exhibited heavy fretting contact damage. Thread impressions were observed, consistent with high-force contact. The cap screws showed fatigue fractures; screw 1 had multiple fatigue origins and fracture on multiple planes, consistent with being the first to fracture.