The Irkutsk Aviation Plant, a branch of Irkut Corporation (a part of UAC), has completed systems diagnostics of the fourth MC-21-300 aircraft designed for flight tests. The results of the first prototypes' testing were taken into account in the aircraft production process. Three of them are undergoing flight tests, two of them are on static tests.

On November 28, the new aircraft was transferred from final assembly shop to the plant's flight-test division.