Russian airframer Irkut has flown its fourth flight-test MC-21-300 to Moscow to participate in the certification campaign for the twinjet.

The aircraft, fitted with Pratt & Whitney PW1400G engines, was ferried with a crew of two pilots to the Gromov institute at Zhukhovsky airfield.

It has been fitted with a passenger cabin consistent with an all-economy layout of 211 seats, says Irkut, although only 172 are currently installed because measurement equipment and engineer stations have been situated in the aft section.

The other 39 seats will be put in place ahead of certification flights, replacing the test equipment.

“With the fully-fitted cabin tests will be carried out – in particular, the emergency evacuation,” says the manufacturer.

Irkut’s third flight-test aircraft, which was presented at the Moscow MAKS air show last year, had a two-class configuration with 163 seats.

Production work is continuing on another test aircraft, the first to be fitted with the alternative Aviadvigatel PD-14 powerplant.