History of Flight
On February 16, 2021, at about 0917 central standard time, an experimental Velocity Vtwin airplane, registration N13VT, sustained substantial damage in an accident near Janesville, Wisconsin. Both pilots were fatally injured. The flight operated under Title 14 Code of Federal Regulations (CFR) Part 91 as a ferry flight, destined for Sebastian, Florida, for landing gear system maintenance. The flight was conducted under an FAA Special Flight Permit, which included limitations requiring the landing gear to remain down and authorizing a co-pilot, though the airplane required only one flight crewmember.
The airplane departed Appleton International Airport (ATW) at about 0634 and landed at Southern Wisconsin Regional Airport (JVL) at about 0715. Fuel records indicated the airplane was serviced with 53.5 gallons of 100LL aviation fuel. The airplane departed JVL around 0912.
Shortly after takeoff, the right-seat pilot reported engine issues and requested to return for landing on runway 32. The controller acknowledged and asked if assistance was needed; the pilot replied no. No further radio communications were received.
Data from the Garmin G3X multifunction display (MFD) showed right engine rpm decreasing from about 2,600 to 2,100 rpm around 0912:15. Airspeed increased to a maximum of about 156 knots and altitude to about 2,850 ft. Right engine rpm fluctuated above 2,100 before decreasing to zero by 0914:10. The airplane descended until data ended. The tower controller observed the airplane in a left turn with increasing bank angle before losing sight behind trees.
Personnel Information
A review of the right-seat pilot's logbook indicated training in the accident airplane in September 2020, with a flight instructor's comment: "Very nice job! Velocity Twin proficient."
Wreckage and Impact Information
The airplane struck trees and came to rest inverted in a 3-ft-deep tributary of the Rock River, about 1 mile south of JVL. Both wings, both canards, and the fuselage sustained substantial damage. Both fuel tanks were breached; a strong odor of 100LL aviation fuel was present.
Both propellers were in the "feathered" position. Left engine controls (throttle, propeller, mixture) were further aft than those for the right engine. The left main landing gear door remained attached; the right main landing gear door was missing. One right engine propeller blade, found at the initial impact tree, had leading-edge impact damage consistent with screw or bolt threads. The other two right propeller blades were not located.
Engine examination revealed no preaccident mechanical malfunctions or anomalies that would have precluded normal operation. The right oil pressure sending unit and wiring harness appeared unremarkable. The left oil pressure sending unit wiring harness had a red wire separated into two pieces and visible cuts in the green and black wires; this damage was not consistent with impact damage.
Testing of both oil pressure sending units on an exemplar Velocity Vtwin showed they could detect oil pressure when installed with appropriate wiring. According to Velocity, if the Garmin G3X fails to receive data from the sender, a red "X" appears over the oil pressure indication.
Medical and Pathological Information
Toxicology testing of the left-seat pilot identified bupropion (741 ng/ml) and its metabolite, as well as amphetamine (58 ng/ml) in femoral blood and urine. Bupropion, marketed as Wellbutrin and Zyban, carries warnings of a dose-dependent risk of seizures and potential impairment for hazardous tasks. Amphetamine, a Schedule II stimulant, has warnings about abuse potential, increased risk of sudden death, and mental health changes. Average blood levels after a single 30 mg dose are 111 ng/ml; with long-term use, about 65 ng/ml. Abuse levels typically exceed 200 ng/ml and may reach above 2000 ng/ml.
Tests and Research
The NTSB conducted a vehicle performance study using data from two Garmin G3X displays and ADS-B data. MFD rate-of-climb data showed a significant decrease shortly after the engine concern was reported, then increased before declining to near zero. Indicated airspeed reached about 156 knots, exceeding the maximum landing gear extended speed (VLE) of 140 knots. Right engine data were consistent with an engine shutdown, with decreasing fuel flow and exhaust gas temperature. No left engine data were stored. MFD data from a previous flight showed operation above VLE and landing gear operation speed (VLo) of 120 knots, despite ferry permit limitations, and fuel flow near 75% cruise power.