For example the very first U.S. Army helicopter units , flying CH - 21 helicopters , that began flying combat missions in Vietnam in 1962 did n't .
Initially however not all helicopters were armed or outfitted with a dedicated MG for door armament .
The very first U.S. Army helicopter units , flying CH - 21 helicopters , that began flying combat missions in Vietnam in 1962 did n't .
Initially however not all helicopters were armed or outfitted with a dedicated MG for door armament .