prototype took place in September 1988 and a contract was signed for 29 upgraded aircraft in December of that year. The Sea Harrier FA2 was fitted with the Blue Vixen radar, which was described as one of the most advanced pulse doppler radar systems in the world. In August 1981, BAe and the American aircraft manufacturer McDonnell Douglas signed a memorandum of understanding regarding the McDonnell Douglas AV-8B Harrier II. Under this agreement, BAe was effectively a subcontractor rather than a full partner, receiving 40 percent of the airframe's work-share in terms of man-hours. Production took place at McDonnell Douglas' facilities in suburban St. Louis, Missouri, and manufacturing by BAe at its Kingston and Dunsfold facilities in Surrey, England. The variant procured for the RAF, which was known as the BAe Harrier II, featured many differences, including avionics fit, armaments and equipment; the wing of the GR5 featured a stainless steel leading edge, giving it different flex characteristics from the AV-8B. In December 1989, the first RAF squadron to be equipped with the Harrier II was declared operational. In 1979, BAe officially joined the multinational aircraft manufacturer Airbus and acquired a 20% share in the venture, the move effectively reversed a decision made ten years prior in which the UK government had withdrawn its support for the Airbus consortium. Airbus' first aircraft, the A300, had been received with little initial demand, but orders for the airliner had picked up in the late 1970s. By 1979, the consortium had 256 orders for A300, and Airbus had launched its second airliner, the A310, less than 12 months prior to BAe formally joining the consortium. As time went on, it was becoming clear that Airbus was no longer a temporary collaboration to produce a single design as per its original mission statement; it had become a long-term brand for the development of further aircraft. By the late 1980s, work had begun on a pair of new wide-body airliners, the biggest to be produced at this point under the Airbus name; these would be launched in the 1990s as the Airbus A330 and the Airbus A340. During the 1983 Paris Air Show, the launch of the Experimental Aircraft Programme (EAP) to develop and fly an advanced fighter technology demonstrator was announced; at this point, the effort was intended to be a partnership between Britain and several of its European neighbours, including West Germany and