The NTSB has concluded that the probable cause of a Grand Canyon helitour that killed five people on Feb. 10, 2018, was “a loss of tail rotor effectiveness, the pilot’s loss of helicopter control, and collision with terrain during approach to land in gusting, tailwind conditions in an area of potential downdrafts and turbulence.” The Airbus Helicopters EC130B4 operated by Papillon Grand Canyon Helicopters crashed at 5:20 p.m. local time in rugged terrain near Quartermaster Canyon on the Hualapai Nation in Arizona, three miles east of the Grand Canyon West Airport. All seven aboard survived the initial impact, but three passengers aboard died in the post-crash fire and another two subsequently died of related injuries. The part-time pilot and one passenger survived with severe injuries.
While the NTSB investigation found no mechanical faults with the accident helicopter, it did uncover questionable weather monitoring practices on the part of both the pilot and the operator. Specifically, the NTSB found that “weather advisories issued after the morning weather briefing, several hours before the accident, indicated a cold front proceeding through the area with associated gusts and turbulence. This information was likely not captured by the operator and distributed to its pilots even though some of the forecasts included wind conditions above the maximum wind outlined in the company’s general operations manual.” The only available wind information at the landing site was a windsock.
According to the NTSB, the accident pilot “would not recheck the weather between tour flights” due to the short turn time between flights to the Grand Canyon and the fact that he had just been there. The National Weather Service issued an urgent weather message for the accident site the morning of the accident that warned of sustained winds of 20 to 30 mph, with gusts to 30 to 45 mph and isolated gusts to 55 mph by 6 p.m. local time. Subsequent to the crash, the winds were so high that they delayed extraction and transport of the survivors into early the next morning.
The helicopter was on approach to landing on a west pad at Quartermaster—the location of the Hualapai’s famous glass Skywalk—when the accident occurred. Two pilots approaching from the same direction who landed immediately before reported “adverse wind.” One pilot said it was so severe that it required application of “full right pedal and nearly resulted in a loss of yaw control.”
NTSB investigators uncovered evidence from a December 2017 line check training that these conditions could have presented a particular challenge to the accident pilot. Specifically, the NTSB found that he “had experienced difficulty maneuvering the helicopter during high wind conditions” and initially received an “unsatisfactory” performance rating from the lead pilot performing preparation for that portion of the line check.
After the accident, Papillon instituted a variety of safety measures, including the fitting of crash-resistant fuel tanks in all of its helicopters and installation of an additional windsock and a weather station at Quartermaster that transmits real-time wind information to Papillon’s base.