 From Clark AB, Garrison was assigned as vice commander of the 8th Tactical Fighter Wing at Ubon Royal Thai Air Force Base, Thailand, in August 1966.The following month Col. Robin Olds was made commander of the 8th TFW to invigorate its combat spirit, and together with deputy commander of operations Col. Daniel "Chappie" James and Garrison, provided one of the strongest and most experienced command triumvirates in Southeast Asia.Garrison flew the F-4C Phantom II on 97 missions over North Vietnam and Laos, although Olds noted that Garrison never formally "checked out" (qualified) in the type, as a result of which he always flew with an instructor pilot in the rear seat.