Boeing 707 center section tanks. Its first flight was on January 11, 1958; 69 turbojet 707-320s were delivered through January 1963, the first passengers being carried (by Pan Am) in August 1959. The 707-420 was identical to the −320, but fitted with Rolls-Royce Conway 508 (RCo.12) turbofans (or by-pass turbojets as Rolls-Royce called them) of 18,000 lb (79 kN) thrust each. The first announced customer was Lufthansa. BOAC's controversial order was announced six months later, but the British carrier got the first service-ready aircraft off the production line. The British Air Registration Board refused to give the aircraft a certificate of airworthiness,
Boeing 707 these variants were built, including a small number with JT3D-7 engines (19,000 lb or 84.6 kN takeoff thrust) and a takeoff gross weight of . Ironically, most −320Cs were delivered as passenger aircraft, airlines hoping that the cargo door would increase second-hand values. The addition of two additional emergency exits, one on either side aft of the wing raised the maximum passenger capacity to a theoretical 219. Only a few aircraft were delivered as pure freighters. One of the final orders was by the Iranian Government for 14 707-3J9C aircraft capable of VIP transportation, communication, and in-flight refuelling tasks. The