939th Air Refueling Wing The 939th Air Refueling Wing is an inactive United States Air Force Reserve unit . It was last active with the Fourth Air Force , based at the Portland Air Reserve Station , Oregon . It was inactivated on 30 June 2008 . Mission . The mission for the 939th Air Refueling Wing was to fly the KC - 135R Stratotanker , providing air - to - air refueling and other worldwide air mobility support in support of the Air Mobility Command and combatant commanders . It consisted of the following units : History . Following the mobilizations in 1961 and 1962 for the Berlin Crisis and the Cuban Missile Crisis , Continental Air Command ( ConAC ) realized that it was unwieldy to mobilize an entire wing unless absolutely necessary . Their original Table of Organization for each Wing was a wing headquarters , a troop carrier group , an Air Base Group , a maintenance and supply group , and a medical group . In 1957 , the troop carrier group and maintenance and supply groups were inactivated , with their squadrons reassigned directly to the wing headquarters - despite the fact that many wings had squadrons spread out over several bases due to the Detached Squadron Concept dispersing Reserve units over centers of population . To resolve this , in late 1962 and early 1963 , ConAC reorganized the structure of its reserve Troop Carrier Wings by establishing fully deployable Troop Carrier Groups and inserting them into the chain of command between the Wing and its squadrons at every base that held a ConAC troop carrier squadron . At each base , the group was composed of a material squadron , a troop carrier squadron , a tactical hospital or dispensary , and a combat support squadron . Each troop carrier wing consisted of 3 or 4 of these groups . By doing so , ConAC could facilitate the mobilization of either aircraft and aircrews alone , aircraft and minimum support personnel ( one troop carrier group ) , or the entire troop carrier wing . This also gave ConAC the flexibility to expand each Wing by attaching additional squadrons , if necessary from other Reserve wings to the deployable groups for deployments . As a result , the 939th Troop Carrier Group was established with a mission to organize , recruit and train Air Force Reserve personnel in the tactical airlift of airborne forces , their equipment and supplies and delivery of these forces and materials by airdrop , landing or cargo extraction systems . The group was equipped with C - 119 Flying Boxcar s for Tactical Air Command airlift operations . The group was one of four C - 119 groups assigned to the 312th TCW in 1963 , the other being the 938th Troop Carrier Group , at Hamilton AFB , California ; 940th Troop Carrier Group at McClellan AFB , California , and the 941st Troop Carrier Group at Paine AFB , Washington . The 939th performed routine reserve airlift operations , being upgraded to the C - 124 Globemaster II intercontinental airlifter in 1966 . On 26 January 1968 the group was activated for combat duty in the Vietnam War . The group flew overseas missions , particularly to the Far East and Southeast Asia during that period , being relieved from active service in June 1969 . Inactivated on 1 July 1973 as part of a reorganization of Military Airlift Command assets , personnel and equipment being assigned directly to its host 349th MAW . Air rescue mission . In 1985 , the unit changed to a rescue mission and the 939th was known as the 939th Rescue Group ( 939 RQG ) , then 939th Rescue Wing ( 939 RQW ) , controlling rescue squadrons at widely separated locations : the collocated 304th Rescue Squadron ; the 301st and later the 39th in Florida ; and the 305th , initially in Michigan until 1 September 1992 and then in Arizona from 1 October 1993 . It provided considerable assistance to Florida and the 301st Rescue Squadron following the devastation of Hurricane Andrew in August 1992 . It also deployed aircrews from each of the squadrons to provide search and rescue ( SAR ) coverage worldwide , including to NAS Keflavik , Iceland , during and after the Southwest Asia War and to provide combat SAR coverage in the Persian Gulf area , 1993 - 2003 . Air Refueling . In 2003 , the 939th converted to an aerial refueling mission with KC - 135R Stratotanker aircraft and was redesignated as the 939th Air Refueling Wing ( 939 ARW ) . Its rescue - specific units ( i . e . , the 304th Rescie Squadron , etc . ) were reassigned as geographically separated units ( GSU ) to the newly established 920th Rescue Wing in Florida . The 939 ARW was inactivated in 2008 due to BRAC action and its KC - 135R aircraft assets redistributed to other Air Force , Air Force Reserve and Air National Guard units . The wing ' s former 304th Rescue Squadron remains in place at Portland ARS as a GSU of the 920th Rescue Wing .