KC-10 Extender airplane model. In late 1977 the USAF selected the DC-10 to meet its Advance Tanker/Cargo Aircraft requirement. Basically, a conversion of the DC-10 Series 30CF, the KC-10 has additional fuel cells in the lower fuselage, an inflight-refueling boom, boom operator's station, inflight-refueling receptacle, and an improved cargo-handling system. Multi-year contracts covered the supply of 60 KC-10As, the first of them being test flown from Long Beach to Yuma on July 12, 1980. Initial deliveries to the USAF began on March 17, 1981, and the last was accepted in April 1990.