The Lockheed C-5 Galaxy heavy logistics transport, now supported by the Lockheed Martin Corporation, is the workhorse of US strategic airlift capability. Key to the C-5's mission capability is its cavernous interior and roll-on/roll-off capability with access to cargo at both ends of the aircraft.
The C-5A first flew on 30 June 1968, and the first operational aircraft was delivered on 17 December 1969 with the last following in May 1973. The C-5A suffered initially from wing crack problems and cost overruns, but has since served well. Between 1981 to 1987 77 of the 81 production C-5As received wings of virtually new design and with greater corrosion resistance.
From 1986 to 1989, the production line was re-opened to manufacture 50 improved C-5Bs that incorporated modifications and improvements resulting from experience with the C-5A. The type provides the most ton-miles at the fastest speed of any American airlifter, and is the largest aircraft routinely operated by US forces. Although not usually assigned airdrop duties, it can also drop paratroops.
The C-5C designation is applied to two aircraft modified with sealed front visor and strengthened interior for the carriage of satellites and space equipment. In recent years the C-5A/B has suffered from serious reliability problems that result in low mission capable rates. The USAF is addressing the shortfall in airlift capacity as a result of the C-141's retirement by considering a range of major modifications to keep its Galaxy fleet operational until 2030. Around 125 aircraft will receive new digital automatic flight controls, new cockpit displays and new communications and navigation equipment. In 2000 the USAF selected the General Electric CF6-80C2L1F turbofan to initially re-engine the 50 youngest C-5Bs. C-5A/Bs equip Air mobility command, Air force reserve command, and Air national guard units. At least two C-5As assigned to Air forces special operations command have a special forces role.