Russian investigators have disclosed that the right-hand main-gear tyres of an Antonov An-24 began to fail within moments of touchdown before the aircraft eventually veered off the runway and fatally collided with obstacles at Nizhneangarsk.
The Angara Airlines aircraft, arriving from Ulan-Ude on 27 June, had suffered failure of its left-hand Progress AI-24 engine while descending to 10,000ft, about 13min before it landed.
Its crew – comprising a captain, who was an inspector pilot, a first officer being assessed for captaincy, and an engineer – feathered the propeller and turned off the autopilot.
Airport services at Nizhneangarsk were put on standby to receive the aircraft, which was cleared for landing on runway 23. The wind direction was given as 060° at 4kt, indicating a tailwind.
Russia's Interstate Aviation Committee says the aircraft touched down initially on its left-hand main gear some 540m from the threshold.
Traces of destruction of the right-hand main-gear tyres began to emerge after the An-24 had rolled just 130m along the runway, says the inquiry.
The aircraft continued for a further 760m before it began to veer to the right and exit the runway edge, moving over rough ground and losing the outer right main-gear tyre.
It travelled about 470m after leaving the runway before striking an airfield fence. The right-hand main-gear strut collapsed and the aircraft continued across a road, hitting obstacles and overturning a car before its left engine collided with a sewage-treatment building.
The impact badly damaged the cockpit and spilled fuel ignited.
While the first officer managed to escape through the left forward emergency hatch, he was unable to help the captain or the engineer, says the inquiry, and neither survived the accident.
Fire destroyed most of the aircraft. The 43 passengers were evacuated through the rear, nine suffering serious injuries.
Investigators state that the captain had logged more than 10,600h on An-24s and An-26s, out of a total of nearly 15,200h. The first officer had just over 6,000h with 1,325h on An-24s.