of the tail fin being composed of glass fibre reinforced plastic. Béteille opted for English as the working language for the developing aircraft, as well against using Metric instrumentation and measurements, as most airlines already had US-built aircraft. These decisions were partially influenced by feedback from various airlines, such as Air France and Lufthansa, as an emphasis had been placed on determining the specifics of what kind of aircraft that potential operators were seeking. According to Airbus, this cultural approach to market research had been crucial to the company's long-term success. Workshare and redefinition On 26 September 1967, the British, French, and West German governments signed a Memorandum of Understanding to start development of the 300-seat Airbus A300. At this point, the A300 was only the second major joint aircraft programme in Europe, the first being the Anglo-French Concorde. Under the terms of the memorandum, Britain and France were each to receive a 37.5 per cent work share on the project, while Germany received a 25 per cent share. Sud Aviation was recognized as the lead company for A300, with Hawker Siddeley being selected as the British partner company. At the time, the news of the announcement had been clouded by the British Government's support for the Airbus, which coincided with its refusal to back BAC's proposed competitor, the BAC 2–11, despite a preference for the latter expressed by British European Airways (BEA). Another parameter was the requirement for a new engine to be developed by Rolls-Royce to power the proposed airliner; a derivative of the in-development Rolls-Royce RB211, the triple-spool RB207, capable of producing of . The program cost was US$4.6 billion (in 1993 Dollars). In December 1968, the French and British partner companies (Sud Aviation and Hawker Siddeley) proposed a revised configuration, the 250-seat Airbus A250. It had been feared that the original 300-seat proposal was too large for the market, thus it had been scaled down to produce the A250. The dimensional changes involved in the shrink reduced the length of the fuselage by and the diameter by , reducing the overall weight by . For increased flexibility, the cabin floor was raised so that standard LD3 freight containers could be accommodated side-by-side, allowing more cargo to be carried. Refinements made by Hawker Siddeley to the wing's design provided for greater lift and overall performance; this gave the aircraft the ability to climb faster and attain a