The Sikorsky S-61N was flying back to a U.S. Navy missile range to return an inert training torpedo when it gradually pitched nose-down and struck the ground in a near-vertical attitude, killing two pilots and two crewmembers, the U.S. National Transportation Safety Board (NTSB) says.
The helicopter, operated by Croman Corporation under contract to the Navy, was destroyed in the Feb. 22, 2022, accident at Pacific Missile Range Facility (PMRF), Barking Sands, in Kakha, Hawaii, U.S.
In its final report on the accident, the NTSB said the probable cause was the “improper installation of the fore/aft primary servo by maintenance personnel.” Because of the incorrect installation, the attaching hardware backed out of place, leaving the helicopter uncontrollable, the report said.
At the time of the accident, the helicopter — which was manufactured in 1962 and had accumulated more than 36,000 hours total airframe time — was participating in submarine training exe…
