Model G-1159A Gulfstream III - Two or three-crew executive, corporate transport aircraft, powered by two Rolls-Royce Spey turbofan engines.
C-20A - United States Air Force variant configured for 14 passengers and five crew; phased out of USAF service in 2002, one example transferred to NASA for use at the Neil A. Armstrong Flight Research Center at Edwards Air Force Base as a test aircraft [REF].