The C-20 Gulfstream III (launched by Grumman American in 1976, its development and production becoming the responsibility of Gulfstream American in 1978 after Grumman sold its interest) is a twin-engine, turbofan aircraft which fills the special airlift mission requirement for high-ranking government and Department of Defense officials. First flown on 2 December 1979, the C-20A was chosen in June 1983 as the replacement aircraft for the Lockheed C-140B Jetstar. The three original aircraft at Andrews AFB, MD were subsequently transferred to Ramstein Air Base, Germany, and all C-140Bs at both locations were phased out of the Air Force inventory. Currently, five C-20Bs are flying special air missions from Andrews. The primary differences between the C-20A and C-20B are the electrical systems and avionics packages.
The C-20G is a Gulfstream IV aircraft that can be configured for cargo or passenger operations, or a combination of the two. With passenger seats removed the aircraft may be modified to the following configurations: three pallets/no passengers, two pallets/eight passengers, and one pallet/fourteen passengers. With a full complement of seats installed, the aircraft is capable of accommodating up to twenty-six passengers and a crew of four. Other features include a hydraulically-operated cargo door installed on the starboard side of the aircraft to facilitate loading and unloading of cargo, a ball-roller cargo floor capable of accommodating palletized cargo, and a walk-in baggage area of 157 cubic feet, fully pressurized, which is accessible from the cabin.
First flown on 19 September 1985, the Gulfstream IV is a stretched version of the Gulfstream III with upgraded features including Rolls-Royce Tay in place of Spey engines, structural improvements, increased fuel capacity, and a modernized cockpit.
In 1992, Gulfstream delivered the C-20H (Gulfstream IV) to Andrews AFB. This aircraft is powered by two Rolls Royce Tay Mark 611-8 turbofan engines, which provide greater performance, greater range and are quieter than A and B models. The C-20H is also slightly longer than A and B models, and has an upgraded avionics package and interior.
The 89th Airlift Wing, Andrews AFB, MD, operates two H-model C-20s for worldwide special air missions.