History of Flight
On September 6, 2022, at 1325 central daylight time, an experimental, amateur-built Glasair Super II SFT airplane, registration N11HC, was substantially damaged when it impacted terrain near Bay City, Wisconsin. The flight instructor and a commercial pilot-under-instruction sustained fatal injuries. The airplane was operating under Title 14 Code of Federal Regulations Part 91 as an instructional flight.
The flight departed Rochester Regional Airport (RST), Rochester, Minnesota at approximately 1218. After performing air work, the flight proceeded to Red Wing Airport (RGK), Bay City, Wisconsin, and entered left traffic for runway 9. ADS-B and GPS data indicated that four circuits of the traffic pattern were flown without touchdown, followed by a fifth pattern. During the fifth approach, the airplane turned onto base leg about 0.5 to 1 mile sooner than previous approaches. The airplane impacted the ground approximately 1/3 nautical mile west-northwest of the approach end of runway 9.
The airplane was equipped with a Garmin G3X integrated flight instrument system. Data from the system showed that after departure, the airplane climbed to about 10,000 ft msl for air work, including level, 60° bank, 2 g turns. The air work lasted about 45 minutes. The airplane then descended at about 4,400 fpm toward RGK. On the accident approach, the descent rate, bank angle, and pitch attitude were higher than previous approaches: descent rate approached 2,500 fpm, left bank angle approached 100°, pitch attitude about 15° nose-down. During the final turn, positive load factor of 1 to 2 g was observed, and lateral acceleration of about 0.3 g was consistent with a side slip. Engine data indicated reduced throttle setting at the last recorded moment at 13:24:53, with fuel pressure 26.1 psi, engine speed 1,590 rpm, and oil pressure 61 psi.
Personnel Information
The owner and builder of the airplane stated the flight was intended to build time for insurance requirements so that the commercial pilot could be added to the owner's policy. It was the first flight for that purpose, and the two pilots had not flown together previously. The flight instructor had flown with the owner on September 1, 2022, performing air work, stalls, patterns, and landings satisfactorily. The flight instructor had no previous experience in the Glasair other than that flight. The commercial pilot had flown as a passenger but had no logged time in the Glasair.
Wreckage and Impact Information
The accident site examination revealed the airplane impacted terrain on a heading of about 045°, and the main wreckage came to rest upright about 80 ft from initial impact. No fire occurred. All structural components were within the wreckage path. The fuselage sustained structural damage and fiberglass skin separation; the header fuel tank was breached with no fuel remaining. The cockpit fuel tank selector was in the "HEADER" position.
Both wings sustained structural damage, including extended-length wing tips. Both wing fuel tanks were breached with no fuel, though the owner reported filling them to 50 gallons before flight. Aileron continuity was confirmed. The electrically-operated flaps were visibly extended; G3X data indicated flaps were in transit to extended positions, with last recorded position 36° (full 40°).
The vertical stabilizer and rudder were damaged; rudder cable continuity was confirmed. Elevators remained attached, and continuity was confirmed via push-pull tube. The engine remained attached to the firewall; propeller remained attached to crankshaft flange, but the flange separated from the crankshaft during impact. Oil leaked from the engine; extensive impact damage to the bottom. The oil sump was mostly missing. Engine examination revealed thumb compression and suction, camshaft-to-crankshaft continuity, correct valvetrain movement, and normal fuel system signatures with no obstructions or contamination. Both magnetos produced spark at all leads. Spark plugs had normal coloration and wear. Nothing was found that would have precluded the engine from making power before impact.
The propeller blades showed one bent aft about 15° with polishing on the leading edge, and the other blade displayed polishing and rotational scoring.
Medical and Pathological Information
Autopsy reports from the Office of the Medical Examiner, Pierce County, Wisconsin, determined the cause of death for both pilots was multiple traumatic injuries due to the airplane crash. Toxicology testing on the flight instructor was performed locally, with no evidence of drugs or ethanol. Toxicology testing on the commercial pilot-under-instruction was performed by the FAA Forensic Sciences Laboratory, also finding no evidence of drugs or ethanol.