The first flight of a B-52B model was on 25 January 1955 and initial delivery to the 93rd Bomb Wing (H) at Castle AFB, CA occurred in the summer of 1955. Although the 93rd BW was considered an operational unit, its primary mission was transition training for new B-52 crews. Eventually, the -B models (RB-52Bs included) were used by the 95th, 99th and 22nd Bomb Wings in addition to the 93rd.
     Trouble began on 16 February 1956, when a B-52 exploded in midair near Tracy, California, while on a flight from nearby Castle AFB. The crash made national headlines, in part because of the B-52's then unprecedented cost of $8 million. Several months later an in-flight explosion claimed a second Castle B-52 and the lives of five crew members. On 16 January 1957, five B-52s thundered down Castle's runway. Their mission was simple: show the world that the B-52 had the capability of becoming the first jet aircraft to circle the world nonstop. Supported by nearly 100 KC-97 tankers flying from Canada, Morocco, Saudi Arabia, the Philippines, and Guam, the three B-52s--led by Lucky Lady III--finished their mission at March AFB, California, on the morning of 18 January. Their flight time--45 hours, 19 minutes--was less than half that required by the B-50 Lucky Lady II just eight years before.
      The base consists of 2,777 acres. The main base contains an airfield, aviation support buildings, warehouses, 1,707 dormitory beds, and a 52 bed hospital. Two housing areas, separated from the main base, include 933 family housing units. Most of the base lies within the unincorporated part of Merced County. Part, however, lies within the City of Atwater.
     The 11,800' runway which is 300' wide, is the 4th longest civilian runway in the state. The nearest airport is in Merced with a 5,900 foot runway. The airport opened in January 1996 as an uncontrolled day-use airport. Castle Airport is designated as a General Aviation Airport, with fueling and pilot services provided by Trajen Flight Support. Primary use of the airport has been general aviation, however, large commercial aircraft companies have showed significant interest. The airport is being positioned for use as a heavy cargo / maintenance / training / manufacturing facility. General aviation activity has been amply provided for with the premier terminal in the area and community hangar and tie down facilities.
     The Castle Air Museum Foundation has been in existence since the Air Force established the base museum in 1981. It is supported by nearly 600 individuals, many of whom are military retirees. When Castle Air Force Base closed in 1995, the Foundation assumed all responsibility for managing and displaying the museum's collection of 44 planes which are on loan from the Air Force, among them a B-24, a B-36 and a SR-71. Just before closure, the Air Force conveyed two buildings and about 20 acres to the Foundation under a public benefit conveyance sponsored by the U.S. Department of Education. Visitation to the museum, currently at 80,000, is expected to increase as the newly opened Challenger Learning Center attracts visitors. In addition, the U.S. Space Camp Foundation in Huntsville, Alabama has opened an Aviation Challenge Program at Castle.
     In mid-1998, the Federal Bureau of Prisons began construction of a new $70-$80 million, 1,000-bed high security federal penitentiary at Castle. Also included in the Castle plan is a 150 inmate minimum-security satellite camp. The initial Bureau plan at Castle included a 1,600 inmate medium-security federal correctional institution. However, federal needs changed and there now is a more urgent need for high-security capacity.