in the face of lukewarm support from airlines for a 300+ seat airbus a300, the partners submitted the a250 proposal, later becoming the a300b, a 250-seat airliner powered by pre-existing engines. this dramatically reduced development costs, as the rolls-royce rb207 to be used in the a300 represented a large proportion of the costs. the rb207 had also suffered difficulties and delays, since rolls-royce was concentrating its efforts on the development of another jet engine, the rb211, for the lockheed l-1011 and rolls-royce entering into administration due to bankruptcy in 1971. the a300b was smaller but lighter and more economical than its three-engined american rivals.