In 1966, the Marines experienced an acute shortage of UH-1Es. Most of the Corps' small number of Hueys were operating in Vietnam with the three VMO squadrons. As losses began to outpace production, it became necessary to strip aircraft from VMO-1 at New River, and send them to Vietnam. As a temporary measure, approval was given to transfer 20 Army UH-1Bs to VMO-1. The first 10 arrived during 1966, with a further 10 coming the next year. Except for one aircraft that was destroyed in an accident, all the UH-1Bs were returned to the Army in 1968.
*Destroyed 23 June 1967 in midair collision with CH-53A 153305.
Note: All these aircraft retained their Army serial numbers, but were repainted Field Green while in Marine service. I haven't been able to find out if they carried VMO-1's "ER" tailcode.
Thanks to Sid Nanson for the serial numbers.