History of Flight
On April 30, 2022, about 0804 mountain daylight time, an experimental amateur-built Bearhawk LSA, registration N1908A, sustained substantial damage during an accident near Kalispell, Montana. The pilot and passenger were fatally injured. The flight was conducted as a personal flight under Title 14 Code of Federal Regulations Part 91.
The pilot planned to fly to Eureka Airport (88M) for breakfast with a group of friends flying in two other airplanes. They departed Kalispell City Airport (S27) about 0759, with the accident airplane as the last in trail.
Other pilots in the group reported an uneventful takeoff with clear skies, good visibility, and no significant weather. They did not see the accident airplane after takeoff but tracked it on their ADS-B receivers until it disappeared a few minutes later.
ADS-B data indicated that after departing from runway 31, the accident airplane climbed on the runway heading for about 4 minutes at a groundspeed of about 88 knots. It then leveled off at a barometric altitude of 4,900 ft (about 1,850 ft agl) and accelerated to about 115 knots over the next 60 seconds, after which the data ended. Closer examination of the altitude data, with a resolution of 100 ft, showed that for the final 3.5 seconds of flight, while maintaining the same track, the airplane descended to 4,800 ft, climbed to 5,100 ft, and then descended again to 5,000 ft as the data ended.
Around that time, a witness heard an unusual wind noise followed by a loud bang and observed a wing falling to the ground. No witnesses observed the initial breakup. A north-facing security camera on a building about 1,100 ft northwest of the last ADS-B target captured the airplane about 1 second before ground impact in a direct nose-down attitude, spinning to the right. The right wing was missing, but the left wing and empennage were still attached and intact.
Personnel Information
The pilot’s most recent FAA medical was in 1997, when he received a third-class medical certificate without limitations. At the time of the accident, he held a valid driver’s license and was flying under light sport pilot provisions. The last entry in his flight logbook was dated May 1, 2019, with no evidence of a current flight review required every 24 months.
The passenger was seated in the rear seat. This flight was the first time she had flown in the airplane with the pilot. Friends noted that the pilot was generally risk-averse and typically flew the airplane solo.
Aircraft Information
The tandem two-seat airplane was designed for the light-sport category and built by the pilot from plans. It had a fabric-covered tubular steel airframe and a conventional aluminum wing, equipped with dual flight controls (rudder pedals and center control stick). Construction was completed and an airworthiness certificate issued in June 2018. The last condition inspection was completed by the pilot on June 3, 2021, and the last logbook entry on February 5, 2022, recorded an oil change with a Hobbs-hour meter reading of 242 hours.
Maneuvering speed (Va) at the estimated accident weight of about 1,357 pounds would have been about 75 mph, based on a stall speed of 35 mph and 4.5 G limit loading. Maximum gross weight was 1,500 pounds in the experimental/utility category and 1,320 pounds under experimental light sport. Never exceed speed (Vne) was 140 mph.
Wreckage and Impact Information
The first identified wreckage piece was the right wing and outboard section of its lift strut, found on a road about 350 ft northwest of the last ADS-B target. The right wing sustained crush damage and abrasions consistent with ground impact after separation; the surrounding tarmac was soaked with fuel. The inboard strut section separated and was found about 100 ft northwest of the wing. The rest of the airplane was located 850 ft northwest of the strut in a flat grass field at an elevation of about 3,090 ft.
The main wreckage came to rest nose-down in a grass field. The airframe sustained extensive crush damage and fragmentation to the leading edge of the vertical stabilizer. The left wing remained partially attached by its lift strut and forward spar end cap.
Bolts connecting the main and aft wing spar end caps of the detached right wing remained in place on the airframe, with wing fittings showing pull-through damage in an upward direction. The lift strut fractured near midspan; the upper section remained connected to the wing attach fitting, while the lower section detached from the landing gear assembly. The lower strut bolt remained at the landing gear weldment, and the clevis fitting on the strut exhibited downward deformation and failure. Concave buckling was noted on the upper side of the strut, and material on the outer side appeared torn out and bent back.
A one-inch-wide impression in the lower lift strut and a rectangular puncture in the lower wing skin matched the dimensions of the right cabin step, with scrape signatures consistent with the step’s anti-slip coating. A 20-inch-wide impact impression in the lower wing leading edge adjacent to the strut attach point matched the diameter of the main landing gear tire, consistent with the wing folding downward against the right side of the airframe.
The tail section remained largely intact; vertical and horizontal stabilizers and rudder sustained minimal damage and remained firmly in place. Rudder control cables were continuous from control surface to foot pedals. Elevator control tubes were breached and buckled in multiple locations. Both ailerons remained attached; right aileron cables were intact to the wing separation point, and left wing drive cable was continuous from control surface to control stick assembly.
The elevator pitch trim control arm was mounted above the pilot to the left; the trim system was intact except for the right trim tab push-pull tube, which had broken away cleanly with no evidence of corrosion.
There was no evidence of a bird strike.
The engine sustained significant impact damage; the starter motor, alternator, ignition wires, cables, and fuel lines were partially detached. The induction system was crushed, and the carburetor detached but appeared largely undamaged. No evidence of catastrophic engine failure; all six cylinders remained attached to the crankcase. The fuel strainer had broken open, exposing a debris-free screen.
The composite two-blade propeller had both blades separated at the root, found in the impact crater next to the engine and propeller hub.
Medical and Pathological Information
An autopsy of the pilot performed by the State of Montana Forensic Science Division reported the cause of death as multiple blunt force injuries. Due to the condition of the remains, medical conditions could not be determined. Toxicology testing by the FAA Forensic Sciences Laboratory was positive for Rosuvastatin (Crestor), a prescription cholesterol medication acceptable for FAA medical certification.
Tests and Research
Examination of the airframe structure revealed that most steel tube walls were about 30% thicker than specified; however, tube widths met plan diameters. Welds were made using the metal inert gas (MIG) arc welding process, contrary to manufacturer recommendations and FAA best practices. The pilot reportedly elected to use thicker gauge tube due to his use of a MIG welder and was aware of the increased weight penalty.
Weld quality was generally poor, with multiple areas of incomplete fusion, porosity, and burn-through. Notably, the left fore-aft lower wing box longeron exhibited an incomplete weld to the left aft vertical support, with no penetration, and had detached. Other airframe welds appeared intact, with separation failures occurring in overload beyond the weld fillets.
The airplane’s plans called for diagonal bracing of the main wing spar carry-through area in the upper cabin, but examination revealed that this bracing was missing. Review of the pilot’s build logs and airframe remnants indicated the bracing had never been installed; nothing suggested the omission was intentional.
The airplane's designer performed a structural analysis calculating the effect of the omitted bracing: the carry-through would lose about 20% of its compressive strength, with little change to tensile strength.
Seat belts: The airplane had two-place lap belts. The front (pilot’s) belt was latched and attached to its anchor fittings. The rear seat had detached from the airframe; its seatbelt was found unlatched with the buckle in a position that would have been in the center of the passenger’s lap. The buckle’s pull tab exhibited downward deformation, but the latch mechanism was still functional.