Ukrainian investigators have strongly criticised South Airlines' operations after finding that an unprepared crew allowed an Antonov An-24 to lose airspeed during approach before it crashed at Donetsk.
Donetsk had been experiencing fog and low-visibility conditions. The pilots had been given accurate and timely meteorological information and landing systems at the airport were operating correctly.
But the aircraft struck the ground with a 48° right bank which tore off the wing, says Ukrainian vice-premier Oleksandr Vilkul, and the An-24 rolled inverted before coming to a halt.
Five occupants were killed in the crash, on 13 February this year, as the aircraft arrived from Odessa.
Vilkul says the inquiry found the pilots were unprepared and not approved to operate under the weather conditions present at the time.
They had been out of flight practice for a long interval, he says, and should not have been permitted to fly without instructor support.
By operating the flight without instructors the captain "overestimated the [crew's] capabilities", says Vilkul, and created the circumstances for the accident.
Nine unregistered passengers had also been among the 52 occupants of the aircraft, in breach of Ukrainian air transport regulations. The inquiry found air traffic controllers did not contribute to the crash.
South Airlines has been prohibited from operating aircraft and investigators are looking at possible criminal proceedings. "As a result of the inquiry, all guilty parties will be held accountable," says Vilkul.