Russia’s United Aircraft has more than 20 Yakovlev MC-21s in various stages of assembly, as it commences certification test flights with its most recent prototype.

The initial certification flight – lasting for 4h, and testing equipment including radio communications – took place at the Gromov flight-research institute at Zhukovsky airfield near Moscow.

This twinjet, powered by Aviadvigatel PD-14 engines, will be used to test several Russian-built systems installed on the aircraft as part of an import-substitution programme.

But state technology firm Rostec, United Aircraft’s parent, says it still retains three foreign-supplied systems – brakes, drives and generators.

Rostec executive director Oleg Yevtushenko says a fully-substituted aircraft, entirely using domestic systems, is undergoing final assembly and “soon…will join the [certification] programme”.

“We are working under tight deadlines, because we understand that airlines are expecting the MC-21,” he says.

“So in parallel with certification we are preparing serial production.”

Over 20 aircraft are already at the manufacturing facility “in various states of readiness”, says Yevtushenko, adding that deliveries to carriers will begin next year.

The prototype was flown from Irkutsk to Zhukovsky in May.

MC-21 chief designer Vitaly Naryshkin says the initiation of certification tests with the jet is an “important stage”, adding that some 220-230 test flights are planned in order to obtain the type certificate.