Flight History
On January 27, 2018, about 1534 Pacific standard time, a Hughes 369D helicopter, registration N369TH, was substantially damaged when it impacted terrain approximately 10 miles northwest of Pomeroy, Washington. The commercial pilot and one crewmember sustained serious injuries, and the second crewmember sustained fatal injuries. The helicopter was registered to McCall Helicopters Inc and operated by Kiwi Air, doing business as Hells Canyon Helicopters, as a Title 14 Code of Federal Regulations Part 91 flight. Visual meteorological conditions prevailed, and no flight plan was filed for the wildlife capture flight, which originated from a nearby staging area.
The purpose of the flight was to capture and collar mule deer for tracking. The operator reported that a wildlife capture flight requires three crewmembers: a pilot, a "mugger," and a "gunner." The pilot sits in the front left seat, the gunner in the left rear seat, and the mugger in the front right seat. On the accident flight, the mugger was training as a gunner, so the helicopter was equipped with two net guns instead of the typical one.
A biologist from the Washington Department of Fish and Wildlife reported that, after about 2 hours of flight, he met the helicopter during a refueling stop when the crew dropped off samples and took on additional collars. During the stop, the pilot mentioned that it was quite windy.
Data from an onboard Garmin 496 GPS unit indicated that after refueling, the helicopter proceeded generally southwest, then turned west, flew south of a ravine, turned northeast through it, then reversed course southwest before the track ended near the accident site.
The pilot did not recall the accident flight. The gunner recalled portions: it was windy, the nets were still opening, the pilot was hovering which was challenging due to wind, and they caught between 5 and 7 deer. He vaguely remembered the mugger working on a deer after refueling and recalled the helicopter spinning shortly before impact.
Personnel and Aircraft
The pilot had about 8 years of experience flying wildlife capture flights and had owned Kiwi Air for about three years at the time of the accident.
According to maintenance logbooks, the most recent maintenance was a 100-hour inspection of the airframe and a 150-hour inspection of the engine, performed on January 17, 2018, at an airframe total time of 11,793 hours and an engine total time of 4,760 hours.
Meteorological Conditions
Station models surrounding the accident site reported west-southwest winds of 25 knots with higher gusts, scattered clouds, temperatures around 40°F, and dew points around 30°F. Nearby airports reported wind gusts between 23 and 35 knots. A High Resolution Rapid Refresh model over the site identified strong low-level winds with a maximum at 1,000 ft above the surface from 230° at 48 knots. Inflight weather advisories included an AIRMET Tango for low-level wind shear and turbulence due to strong winds.
Accident Site and Wreckage
The accident site was located in a small northeast-to-southwest-oriented ravine about 6 miles west of the refueling location. The helicopter came to rest on its right side at the bottom of the ravine with its nose oriented northeast. Impact marks along the lower western ravine wall were consistent with the helicopter's two skids; the right skid was fracture-separated. The cabin was mostly intact, though the right side and floor sustained crush damage. The main rotor head was intact, with one blade wrapped around it; four other blades were fracture-separated, with tips scattered to the south. The tailboom was fracture-separated about 2½ ft forward of the empennage, which came to rest just north of the cabin. The tail rotor assembly and transmission were found just north of the main wreckage slightly up the western ravine wall. A mostly closed net with one extended weight showing damage and a missing rubber ring was located further north, along with a second half-opened net, a piece of tail rotor skin, and a main rotor blade tip cap.
Postaccident Examination
A borescope examination of the gas generator turbine revealed no evidence of operational damage, thermal discoloration, or abnormal combustion, though metal splatter was observed on the first stage turbine nozzle shield. The compressor showed damage consistent with foreign debris but moved freely when rotated by hand. Control continuity from cockpit to engine could not be established due to fuselage deformation. All pneumatic engine control lines were intact and fittings secure.
The forward fuselage exhibited substantial impact damage, with the right side crushed inward. Control continuity from cyclic, collective, and anti-torque pedal controls could not be established due to broken and seized flight controls. The main rotor hub showed multiple fractures and deformation, as did the pitch housing assemblies, swashplates, strap packs, dampers, and blades. Continuity was established from the engine through the main drive shaft to the main transmission, and up to the main rotor hub and back to a fracture in the tail rotor drive shaft. The tail rotor drive shaft was fracture-separated into three pieces with extensive rotational scoring toward the aft end.
The empennage was mostly intact. Light-colored diagonal marks were observed on the tailboom adjacent to the tail rotor. The tail rotor assembly and transmission were fracture-separated from the tailboom; four connecting bolts showed damage—two sheared, one missing, one bent. The tail rotor transmission rotated freely. Contact marks and dents on the tail rotor stop and hub were consistent with excessive blade flapping. One tail rotor blade was undamaged; the second sustained damage to the outboard two inches, and its skin was fracture-separated with denting and bending. The blade tip weight and endcap were fracture-separated and not located.
Tailboom fragments and tail rotor skin were sent to the NTSB Materials Laboratory. The tail rotor blade leading edge exhibited a dent with gouge marks displaying metal transfer (iron, nickel, chromium) consistent with stainless steel similar to net weight material. The net weight also showed metal transfer consistent with contact with aluminum.