Ukraine and Russia are set to sign off on a joint production deal to modernize the An-124 heavy lift transport aircraft, with the final document to be signed in September, a Ukrainian government news bulletin said Friday.

The technical details were agreed during the MAKS 2013 airshow just outside Moscow, and the two countries will ink the final deal at a high-profile bilateral meeting in September, the bulletin said.

Ruslan planes that are nearing the end of their service life will be modernized and upgraded with new, Ukrainian-made, D-18T engines to be installed at Russia’s Ulyanovsk plant. The navigation system, landing gear and avionics will also be replaced, extending the An-124’s service life through 2025.

Ukraine’s Deputy Prime Minister Yuriy Boiko said that a report by audit firm Ernst&Young indicated production should be profitable provided orders come in for more than 40 aircraft.

Boiko noted that Ruslan, in its basic modification, costs $300 million, and that there are currently optional orders for 61 aircraft, 50 of which from Russia’s Volga-Dnepr carrier.

Experts estimate market demand to 2030 for this aircraft at approximately 200.

A single Antonov An-124-100 can carry up to 120 tons of cargo, including ‘outsize’ cargo.

In December 2012, Ukraine’s Antonov design bureau said that NATO had called the heavy lift plane “unique” and said it would continue using it through 2014.