Irkut's MC-21-300 has passed a crucial strength test for its composite wing, the Russian ministry of industry has declared.
The wing had been undergoing stress testing at the Central Aerohydrodynamic Institute but had required reinforcement following load testing earlier this year.
"Truthfully, we were very worried, watching the progress of the wing loading [during the test]," says the institute's general director Sergei Chernyshev.
But he says the results of the test have "exceeded our expectations" and that the wing has "successfully passed" the critical development mark.
The wing was subjected to upwards bending to the point of destruction, says the ministry, and that the experiment has confirmed that the design has "additional margin of safety" over its design load.
Trade minister Denis Manturov claims the experience and specialist knowledge gained during the manufacture of the MC-21's composite wing will be "in demand" around the world.