Failure by the crew to abort an approach in poor weather led to the crash of a Russian-operated Antonov An-24 near Igarka two months ago, an investigation committee has concluded.
The crew allowed the An-24, operated by Katekavia, to descend below the minimum safe altitude of 100m (330ft) despite the absence of reliable visual contact with the approach lights of the runway.
It had been attempting an NDB approach in darkness, following a flight from Krasnoyarsk, when the twin-engined aircraft started deviating to the right of the glidepath to Igarka's runway 12.
The An-24 was banking about 10-15° to the right when it collided with trees, at a height of some 6m, about 480m from the threshold of the runway and over 230m to the right of the centreline.
Twelve of the 15 occupants - including all 11 passengers and a flight attendant - were killed in the impact and the subsequent fire.
Investigation of the accident has been hampered by incomplete flight-recorder data. The cockpit-voice recorder stopped operating around an hour into the flight.
But Russia's Interstate Aviation Committee (MAK), in its final inquiry report into the 3 August crash, states that the flight did not receive reliable support from meteorological services.
© Interstate Aviation Committee
It says that the automated measurements of the weather conditions, notably the height of the cloud base, "contradicted" the observations of two other An-24 crews, ground personnel, and rescuers at the crash site.
MAK refers to the fatal loss of a UTAir Tupolev Tu-134 on approach to Samara in March 2007 and says that the timely implementation of recommendations to improve meteorological support could have prevented the An-24 crash.
Pilots of another Katekavia An-24, which attempted the approach 10min after the ill-fated flight, opted to execute a low-level go-around and divert to an alternate airport. MAK states that this crew similarly "violated the requirement" to abort the approach earlier in the descent.