Russian investigators indicate that an Antonov An-28 which crashed into terrain during a regional service in the far east of the country was far off course before the accident.
The aircraft had been operating from Petropavlovsk-Kamchatsky north to Palana, but hit trees on a mountain known as Pyatibratka, at a height of about 320m (1,050ft) above sea level and nearly 11km (6nm) southwest of the airport.
Recovery teams located the flight-data recorder at the accident site but also retrieved a GPS satellite navigation receiver.
Federal transport supervisor Rostransnadzor says it had identified 17 violations of civil aviation regulations during inspections of the carrier, Petropavlovsk-Kamchatsky Aviation Enterprise, since 2011. It has not detailed their nature.
However, it ordered that another An-28 operated by the airline be grounded until measures had been taken to reduce air safety risks and identify the cause of the accident.
Flight 251, transporting 12 passengers and two crew members, had been intending to carry out an approach to Palana's runway 11 on 12 September.
Weather conditions at the airport - visibility of 6km and a cloud base of 470m - were within limits, says the investigating Interstate Aviation Committee, but "the mountains were covered by clouds".
The approach initially involves flying to a non-directional beacon sited 510m northeast of the airport, ensuring a minimum altitude of 2,150m, in order to reach a holding point and prepare for arrival.
But the actual track of the aircraft, captured by the GPS receiver, showed that - while the pilots had informed they had reached the beacon - the aircraft had been 22km away from it.
Investigators are conducting fuel tests as part of the inquiry but flight-data recorder information shows no evidence of engine failure, or problems with the aircraft, before impact. The An-28 was within weight and balance limits and sufficiently fuelled.
Both engines stopped after the first impact with trees, an aspect of the crash still under examination, but the An-28 continued to fly for 8s before striking the ground. Only four of the occupants survived.
Major sections of the aircraft were found at a height of 216m above sea level, at a distance of 10.7km on a bearing of 219˚ from the airport.