History of Flight
On October 15, 2015, at approximately 1707 mountain daylight time, an Aviat Aircraft Incorporated Husky A-1C-200, registration N280TB, impacted mountainous terrain about 13 miles east of Swan Valley, Idaho. The airline transport pilot was fatally injured, and the passenger sustained serious injuries. The airplane was operated under 14 CFR Part 91 as a local personal flight. Visual meteorological conditions prevailed; no flight plan was filed. The flight departed Alpine Airport (46U) in Alpine, Wyoming, around 1646.
The accident aircraft was flying in loose formation with another Husky of the same type. The second pilot stated that the pilots intended to fly over a reservoir and dam, then climb to view remote lakes, but the exact routing was not discussed. After flying around the reservoir, both airplanes climbed, with the accident airplane leading. As they neared a ridgeline, the second pilot radioed that he would perform a 360° climbing turn to gain altitude before crossing; the accident pilot acknowledged. Upon completing his turn, the second pilot noticed a dust cloud and realized the lead airplane had impacted terrain. He circled to assist in notifying authorities and recovery.
Data from the accident airplane's electronic engine display, recorded on a compact flash card, showed the flight lasted about 24 minutes, with departure at a user-set time of 17:46. Engine power remained near maximum (2,670 rpm) throughout. In the final minute, the airplane was initially at 76 knots and climbing at 742 feet per minute (fpm). Subsequently, airspeed gradually decreased, and climb rate varied widely. During the last five seconds, airspeed was between 48 and 50 knots, and climb rate fluctuated between 7 and 610 fpm. Recording stopped at an indicated pressure altitude of 8,587 ft.
The rear-seat passenger reported that before impact, the airplane was in a turn with normal engine sound, and she heard a steady beeping noise—consistent with the aircraft's stall warning system.
Personnel and Aircraft
The pilot, aged 43, held an airline transport pilot certificate with multi-engine and single-engine land ratings, as well as a flight instructor certificate. He had a first-class medical certificate issued April 2, 2015, with no limitations, and reported 9,500 total flight hours, with 400 hours in the preceding 180 days.
The two-seat, high-wing, fixed-gear airplane was manufactured in 2015 and powered by a 200-horsepower Lycoming IO-360-A1D6 engine with a Hartzell constant-speed propeller. Airframe and engine logbooks were not located. The airplane's weight and balance were within limits. The flight manual listed stall speeds: 50 knots at 0° bank, 54 knots at 30° bank, and 60 knots at 45° bank; with 30° flaps, stall speeds were 46, 50, and 55 knots respectively. The stall warning sounded as a steady tone at 53 mph. At 10,000 ft, best angle-of-climb speed was 61 knots and best rate-of-climb speed was 59 knots. Given the day's conditions, the airplane's maximum climb rate was about 400 fpm; service ceiling was 17,500 ft msl.
Meteorological Conditions
At 1651, weather at Jackson Hole Airport, about 25 miles northeast, reported calm wind, 10 statue miles visibility, clear skies, temperature 20°C, dew point -1°C, altimeter 30.31 inHg. Weather modeling near the accident site indicated horizontal wind 6 knots or less, vertical wind less than 400 fpm. No significant weather advisories were active. Density altitude at the site was about 10,992 ft.
Wreckage and Impact Information
The accident site was at about 8,800 ft elevation, near a ridgeline. Debris was within 50 ft of the main wreckage. The first identified point of contact (FIPC) was a 1-ft by 8-inch by 6-inch disturbed dirt area west of the main wreckage. About 10 ft from the FIPC was another disturbed area with a propeller blade. The fuselage came to rest upright on a heading of about 4° magnetic, 50 ft from the FIPC. Wings remained partially attached. Flight control continuity was established. Fuel leaked from a left wing perforation; right wing fuel sight gauge showed 1/8 full.
The left wing was partially attached and perpendicular to the fuselage; its outer portion crushed, leading edge scratched. Left wing forward strut bent upward, outer strut bent downward. Left aileron and flap attached; flap appeared extended. The right wing was partially attached; inboard leading edge crushed upward, outboard half damaged. Right forward strut bent upward near wing attach point. Aileron and flap partially attached; flap appeared extended.
Main cabin area had impact damage; windscreen shattered, side fuselage wrinkled. Some support structure in front of cockpit was cut by rescue personnel. Engine was angled about 45° to the right; both propeller blades separated but were present. Empennage relatively intact; rudder and elevators attached; right horizontal stabilizer and elevator had impact damage.
Examination revealed no mechanical malfunctions or failures that would have precluded normal operation.
Medical and Pathological Information
The Bonneville County Coroner's Office conducted an autopsy and determined the cause of death as blunt force trauma. FAA toxicology tests were negative for carbon monoxide, cyanide, volatiles, and drugs.