Yakovlev and Tupolev expect to know within a few months which of them has won a contest to supply Aeroflot, the Soviet airline, with hundreds of medium-range airliners.

The result of the competition the two design bureaus have entered will mean life or death for the three designs involved.

Aeroflot has a requirement for a long-overdue Tupolev Tu134 replacement and was believed to be taking the Tu-334 as part of a long-term re equipment strategy.

Following delays in the Tupolev development, however, the airline has received bids from Yakovlev with two versions of a stretched Yak-42, known as the Yak-46. Despite the delays, Tupolev says its bid is aimed at an entry-into-service by 1994.

Tupolev has proposed a two stage development of the Tu334. The initial design, powered by two Progress (ZMKB and formerly Lotarev) D-436T turbofans, will carry up to 102 passengers. A...