the 376th Strategic Wing at Kadena AB, Okinawa, the 305th AREFW at Grissom AFB, Indiana, and the 6th Strategic Wing at Eielson AFB, Alaska. In 1982 the aircraft was modified with Pratt & Whitney TF33-PW102 engines and other modifications common to the KC-135E tanker program, and returned to Eielson AFB. It crashed while on approach to Valdez Airport, Alaska on 25 February 1985 with the loss of three crew members. The wreckage was not found until August 1985, six months after the accident. RC-135U Combat Sent The RC-135U Combat Sent is designed to collect technical intelligence on adversary radar emitter systems. Combat Sent data is collected to develop new or upgraded radar warning receivers, radar jammers, decoys, anti-radiation missiles, and training simulators. Distinctly identified by the antenna arrays on the fuselage chin, tailcone, and wing tips, three RC-135C aircraft were converted to RC-135U (63-9792, 64–14847, & 64–14849) in the early 1970s. 63-9792 was later converted into a Rivet Joint in 1978, and all aircraft remain in service based at Offutt Air Force Base, Nebraska. Minimum crew requirements are 2 pilots, 2 navigators, 3 systems engineers, 10 electronic warfare officers, and 6 area specialists. RC-135V/W Rivet Joint The RC-135V/W is the USAF's standard airborne SIGINT platform. Missions flown by the RC-135s are designated either Burning Wind or Misty Wind. Its sensor suite allows the mission crew to detect, identify and geolocate signals throughout the electromagnetic spectrum. The mission crew can then forward gathered information in a variety of formats to a wide range of consumers via Rivet Joint's extensive communications suite. The crew consists of the cockpit crew, electronic warfare officers, intelligence operators, and airborne systems maintenance personnel. All Rivet Joint airframe and mission systems modifications are performed by L-3 Communications in Greenville, Texas, under the oversight of the Air Force Materiel Command. All RC-135s are assigned to Air Combat Command. The RC-135 is permanently based at Offutt Air Force Base, Nebraska, and operated by the 55th Wing, using various forward deployment locations worldwide. Under the "BIG SAFARI" program name, RC-135Vs were upgraded from the RC-135C "Big Team" configuration. RC-135Ws were originally delivered as C-135B transports, and most were modified from RC-135Ms. This is the only difference (If the aircraft are still equipped with the TF-33, then one of them has thrust reversers and the other one not, that's why they used V and W) between the V and W variants;