Russian airframer Irkut is to install a high-density seating layout in its fourth flight-test MC-21-300 aircraft.

Irkut says the all-economy cabin of aircraft 004 will have 211 seats. The aircraft will be configured with a 28in seat pitch in the forward part of the cabin and 29in in the aft.

The slimline seats will be 18.5in wide allowing a 19.6in aisle, the airframer adds.

Irkut says this aircraft “has been assembled” and that it is undergoing systems fitting. The twinjet will be equipped with Pratt & Whitney PW1400G engines.

The airframer disclosed the cabin plan during the Turkish Teknofest event in Istanbul, where it is displaying the 003 flight-test aircraft.

Irkut has configured 003 – number 73054 – with 163 seats in two classes, including 16 in the business cabin where the seat pitch is 36in.

It says the 147 economy-class seats have a pitch of 32in in this layout. The manufacturer points out that the cabin width of 4.06m allows more freedom for passengers to pass carts in the aisle.

“For our customers we offer a wide range of cabin configuration variants,” it adds.

Irkut has been planning to use a fifth aircraft for tests, the first serially-built airframe, and equip it with Aviadvigatel PD-14 engines.

“Units and components for the aircraft intended for customers are under production,” it states.