Russian authorities are investigating the premature descent of an Airbus A320 which led to the aircraft performing a go-around while several kilometres short of the runway.
The incident, which occurred on 28 February, has been disclosed by French investigation authority BEA in a weekly bulletin.
It states that the aircraft (EX-32002), operating on behalf of Kyrgyz Airways, had been on final approach to Irkutsk's runway 30 and was 25.1km (13.5nm) from the threshold at a height of 780m (2,560ft).
After the A320's glideslope mode was activated the aircraft began descending, the BEA bulletin states.
After 48s the crew turned off the autopilot and executed a go-around at a height of 160m, while still 21.3km from the runway. The twinjet, with 171 occupants, landed safely at the second attempt.
The bulletin says that "wrong functioning" of the runway 30 instrument landing system "contributed to the premature descent".
Weather data for Irkutsk airport at the time of the incident, which occurred in daylight, indicated good visibility.
BEA has not given any further details regarding the apparent ILS problem.