Russian and Ukrainian manufacturers of the Antonov An-148 and An-158 have agreed a new co-operation pact covering key structures for the twinjets.
Voronezh-based airframer VASO says it proposed the new arrangement to Antonov following an increase in production efficiency at the Russian plant.
This means the Russian operation can cover demands for fuselage panel assemblies, and the Ukrainian side will only provide wings to the Russian operation.
VASO production director Alexander Yarchevsky says better organisation and management of the areas supplying structures to Antonov has resulted in lower costs and a shortening of manufacturing times.
General director Vitaly Zubarev says the contracts will be revisited "if the production rate for the An-148 needs significantly to increase".
The new plan was approved at a joint Russian-Ukrainian meeting held in Voronezh at the end of last year, says VASO.
Zubarev says the new agreement is in line with the "economic realities" regarding the civil aircraft industries in the two countries.