Russia's federal air transport authority, Rosaviatsia, is to restrict the operations of carrier Aeroflot-Nord, after a final investigation report into the fatal Boeing 737-500 loss at Perm last year detailed a catalogue of problems.
Rosaviatsia is also warning that it will ground the airline if it fails to address the problems within the next three months.
Aeroflot-Nord has been banned from international air charters and from operating aircraft with deferred defects. The restrictions take effect from 15 June.
Rosaviatsia has ordered the carrier to resolve all outstanding deficiencies by 1 September or its air operator's certificate "will be revoked". Aeroflot-Nord must also provide, before 1 July, a plan to improve its financial position.
Russia's Interstate Aviation Committee (MAK) determined earlier this year that the crash of flight SU821 on 14 September last year was due to the crew's spatial disorientation, partly as a result of unfamiliarity with the 737's instrumentation.
But the inquiry has also highlighted maintenance issues stated that the aircraft was dispatched with two minimum equipment list items - the traffic collision-avoidance system and the autothrottle - inoperative.
© Interstate Aviation Committee
The aircraft was also permitted to operate with an uncorrected throttle-lever 'stagger' condition, in which the two levers were misaligned from one another - by as much as 15° - when the engines were developing the same thrust.
"Despite the numerous records in the technical log this defect was not troubleshot by the maintenance staff," says MAK.
It says the failure to rectify the problem, which had been present for over a month and the "many prolonged" deferrals of minimum equipment list items in the whole 737 fleet shows up a "low level" of 737 maintenance and training of staff at Moscow Vnukovo's VARZ-400 servicing base.
MAK has also stated that the SU821 commander's performance was affected by alcohol and fatigue.