which incorporated an integral loading ramp, while a stronger cargo floor was also installed. A pair of additional doors were fitted, one each on the starboard and port sides, which enabled paratroopers to exit. The military Argosy was powered by an arrangement of four Rolls-Royce Dart 101 turboprops and possessed twice the range of the civil Series 100. From July 1960, the second Argosy Series 100 was used to flight-test the new clamshell door design. On 4 March 1961, the first of the 56 Argosies destined for RAF service performed its first flight. Early on, civil operator British European Airways (BEA) had shown open interest in the Argosy, the company viewed the aircraft as a potential replacement for its existing piston engined freighters; however, evaluations of the Series 100 soon found that its payload capacity would not allow for the type to operated profitably. Early on, as a measure taken to reduce design costs, the wing of the Argosy had been based on that of the Avro Shackleton, a maritime patrol aircraft that was developed and built by another entity within the Hawker Siddeley Group; in order to satisfy BEA's requirements, a new wing was designed which shared the same aerodynamic design, but benefitted from a more modern "Fail safe" structure rather than the Safe-life design used on the earlier wing. This change resulted in a wing that was both stronger and lighter, but was also no longer limited in terms of its fatigue life. The revised version, designated as the Series 200, also featured several other improvements, including the adoption of enlarged cargo doors, integral wing fuel tanks and a modified landing gear arrangement. The Series 200 reportedly had better handling than the older Series 100, although some aerodynamic refinements were required during testing. On 11 March 1964, the first Series 200 aircraft conducted its first flight; it was soon followed by six more Series 220s, which were outfitted with more powerful engines. While work had commenced upon another Series 220, this airframe was never completed and was ultimately scrapped. According to aviation periodical Flight International, the Argosy had been negatively impacted by the emergence of the long-haul passenger jet, as many surplus propeller-driven aircraft had been converted to freighters during this era, thus driving down both demand and prices for new-build cargo aircraft. Design The Armstrong Whitworth Argosy was a general-purpose transport aircraft largely used for freight operations