History of Flight
On July 21, 2022, at approximately 1642 mountain daylight time, a Columbia Helicopters CH-47D, registration N388RA, was destroyed in an accident near North Fork, Idaho. The helicopter was operating as a public aircraft under contract with the United States Forest Service (USFS) for firefighting operations related to the Moose fire. It had been relocated to the area two days prior and began firefighting flights the day before the accident. The helicopter was equipped with a 2,600-gallon water bucket attached to a belly-mounted cargo hook via a 200-foot long line. On the day of the accident, the pilots had flown about 1.5 flight hours and completed multiple bucket drops.
A 38-second video recorded by a local resident showed the helicopter setting up to dip the water bucket into the Salmon River. At the start, the helicopter was hovering about 200 feet above ground level with the empty bucket swinging near the river surface. It then climbed to about 325 feet over 8-9 seconds while maintaining heading. The helicopter began to yaw left, and after a 180° turn, it suddenly pitched down, continued yawing left, and descended. The left yaw persisted until the helicopter impacted the river and riverbank.
Personnel Information
The pilot had completed a USFS vertical reference demonstration and proficiency check on June 27, 2022, using a 200-foot long line. He reported 38 hours of vertical reference flight experience, including 18 hours in a Boeing BV234 (civilian variant of the CH-47D). An FAA letter of competency approved him for Class A, B, and C external loads in the CH-47D, and he demonstrated proficiency in Part 137 firefighting operations. The copilot completed initial training for second-in-command duties in the CH-47D on February 27, 2022, conducted by Columbia Helicopters. He had 6.6 hours as pilot-in-command during training and repositioning. The day before the accident, he accumulated 3.5 hours as second-in-command, and on the accident day, about 1.5 hours, all on Moose fire flights.
Aircraft Information
The CH-47D was originally manufactured by Boeing for the U.S. Army and certified under the restricted category. It features two three-bladed rotor systems in a tandem configuration. Maintenance records as of July 20, 2022, showed an aircraft total time of 7,735.9 hours and Hobbs time of 69.5 hours, with no unresolved discrepancies or anomalous trends.
Wreckage and Impact Information
The helicopter came to rest mostly upright in the Salmon River, with the aft fuselage and pylon partially separated. Both engines remained installed. The lower airframe exhibited upward deformation from impact. Cockpit doors were separated. Rotor blades showed fragmentation at outboard ends. Flight controls were examined: the pilot's cyclic moved freely but longitudinal control tubes were fractured; the copilot's cyclic was partially fractured. Yaw control components were continuous, with jam indicators extended on the yaw and thrust ILCAs. The left yaw/right roll control rod was fractured in overload. No hydraulic system issues were found.
Additional Information
The operator's company operations manual prohibited use of portable electronic devices during critical phases of flight, with exceptions for emergencies. On July 19, 2023, following the investigation, the USFS issued interagency safety alert IASA 23-01 addressing PED safety and security.
Flight Recorders and Medical Information
The helicopter was not equipped with cockpit voice or flight data recorders. Autopsies of both pilots determined cause of death as multiple blunt force injuries, with no significant natural disease identified. Toxicological testing of the pilot detected caffeine; the copilot's testing showed ketamine and its metabolite, attributed to post-accident medical treatment.
Tests and Research
During recovery, a tablet computer (Apple iPad) was found in the river near the cockpit, with three gouge marks on one long side. The NTSB conducted a simulation using a CH-47D simulator to estimate flight control inputs matching the accident video. The simulation indicated that a left pedal input of about 50% was needed for the initial turn, with the pedal reaching its forward stop for the remainder of the flight. Component testing of the yaw ILCA found it functioned within limits. The aft swiveling UBA exhibited smooth actuation after replacement of missing lee plugs. Further investigation examined the iPad's potential to jam the pedal system: with an exemplar helicopter, an iPad placed in the copilot's left pedal area could become jammed, preventing pedal recentering. The gouges on the iPad aligned with a sharp metal part of the heel slide support assembly. Neither a 5'7" nor a 6'2" male could reach the iPad when seated with restraints, and the accident copilot was 5'10" tall.