Russian federal air transport regulator Rosaviatsia has approved the use of import-substituted composites for the vertical fin and horizontal stabiliser of the Yakovlev MC-21.

This formal approval of the amended MC-21 type certificate completes the project to integrate domestically-sourced composites into the twinjet’s design, the regulator states.

Serial production of the composite fin and stabiliser box structures is being carried out by Kazan-based KAPO-Komposit – a division of specialist AeroKompozit.

Rosaviatsia chief Dmitry Yadrov says the reliability of the structures for use in the MC-21 has been “confirmed by calculations, modelling and full-scale testing” in co-operation with the country’s science and certification centres.

The regulator had previously approved the domestic composite wing of the MC-21, as well as the replacement of the Pratt & Whitney PW1400G engines with the Russian-built Aviadvigatel PD-14.

Rosaviatsia’s latest acceptance for the tail structures was granted in December, following work conducted by civil aviation research institute GosNII, the Central Aerohydrodynamic Institute, and other organisations.

United Aircraft chief Vadim Badekha says the aerospace firm has “completely eliminated foreign materials” from the twinjet and “confirmed the reliability” of domestically-produced altenatives.

“Obtaining approval for the use of domestic composites in the MC-21 vertical stabiliser and tail fin marks the completion of an important stage of import substitution,” he adds.

Certification of this import-substituted version of the MC-21 is still under way.

Russian transport minister Andrei Nikitin says the aircraft will “soon begin to be delivered to airlines” and enable them to establish operations that are “completely independent of foreign technology”.