Irkut has given few details of an incident during flight-testing of the latest MC-21 prototype after the aircraft experienced an issue relating to its landing-gear.
The third flight-test airframe, number 73054, returned to Moscow's Zhukovsky airport at about 11:30 on 3 October, after a flight of around 1h.
Irkut says that "a number of new systems" were tested during the operation, and that the tests typically involve different flight modes.
It acknowledges that a landing-gear deployment indication "malfunctioned" during the final stages of the flight, without elaborating as to the actual status of the undercarriage.
There are preliminary indications that the aircraft executed a go-around as it conducted its first approach to runway 30, subsequently touching down after flying a circuit.
Irkut has not specified whether an emergency was declared during the event. It says a standard review will be undertaken to analyse the flight test and technicians will, if necessary, adjust systems accordingly.
One of three aircraft in the current flight-test fleet, 73054 first flew on 16 March and was transferred from the fitting centre at Ulyanovsk to Moscow Zhukovsky for test work on 13 May.