Tupolev is to help a Chinese operator of a Rolls-Royce-powered Tu-204-120 freighter to modify the jet as an airborne laboratory.
The aircraft, which had been delivered in 2008 to Air China Cargo under a deal for the supply of five freighters, was then handed over to Xian Aviation and Technology Company.
"Following recent negotiations with Xian, we signed an agreement to assist it in reconfiguring the aircraft as a flying laboratory for research purposes," said the type's chief designer Oleg Alasheyev.
"We'll start doing this work after receiving technical specifications and detailing terms and conditions with them."
Tupolev adds that it "would not rule out prospects" for the supply of further Tu-204-120s to Chinese customers, given the "apparent interest" in this type.