In the early 1970s four Caribous were used by the US Army at the Kwajalein Missile range on the Marshall islands in the Pacific. These had been taken over from a private company in 1970 and were assigned serials based upon the c/n. This one, c/n 256, became 66-256, despite the fact the 66-0256 had already been assigned to a F-4D Phantom. Later, US Army C-7As were used for this job, followed by C-23Cs, Dash-7s and Be1900s. The fate of this DHC-4A remains unknown.