Russian authorities have restricted the operating certificate of Saratov Airlines following inspections of the carrier in the aftermath of a fatal Antonov An-148 crash.
Federal air transport regulator Rosaviatsia has limited the validity of Saratov's certificate to 27 April.
Saratov has also been ordered to stop all An-148 flights. The airline had previously undergone a suspension of operations with the twinjet type.
While the carrier will be able to continue conducting services with other aircraft, Rosaviatsia says it must eliminate all the "violations and inconsistencies" in its operations uncovered during an unscheduled inspection.
"A decision on further activities of the airline will be taken based on work done by the carrier," it says, adding that the An-148 suspension will be enforced until the authority is satisfied that Saratov's shortcomings have been "fully eliminated".
Saratov has simply pointed out that its operating certificate remains valid and it is able to operate services with Embraer 190s and Yakovlev Yak-42s.
Saratov suffered the loss of an An-148 on departure from Moscow Domodedovo on 11 February. Preliminary inquiries have pointed to unreliable air data and an unheated pitot-static system on the jet.
The airline also experienced an incident on 28 February during which a Yak-42 suffered an engine problem, which led to the crew's shutting it down, before conducting an approach to Domodedovo.
Federal transport supervisory agency Rostransnadzor says it has broadened inspections of An-148s beyond Saratov to other Russian carriers, to establish whether they comply with established airworthiness standards.
It has not taken any decision on whether to suspend An-148 operations at these other airlines.
Rostransnadzor says 15 An-148s are used in Russia. The Russian registry lists 16 of the type, including five with Saratov, another five with Angara Airlines, with the rest split between federal security service FSB and the government's special flight detachment.