Grounded Russian carrier Red Wings indicates that it intends to respond to all the findings which resulted in its flight suspension, but appears suspicious about the decision.
Federal air transport authority Rosaviatsia ordered the grounding from 4 February, citing the findings of an unscheduled inspection of the carrier.
The airline points out that it has been regularly checked by Rosaviatsia and the transport supervisory authority Rostransnadzor, and claims an audit committee in September 2012 determined Red Wings continued to meet certification requirements.
Red Wings adds that Rostransnadzor completed an audit on 28 December, with 18 findings, two of which were dealt with immediately. Another 10, it says, have since been addressed and work on the remaining six is in progress.
"None of these prevented the company from continuing to operate," it says. Red Wings also claims it has not received formal notification of the reasons for the grounding.
Once it has the documentation, it says, it will "respond promptly" to the matters in order to reinstate flight operations.
Red Wings is the largest airline user of the Russian-built Tupolev Tu-204, and the grounding is a further setback to the Tupolev Tu-204SM programme, for which the airline had been the only tentative customer.
The Tu-204SM is a modernised version of the twinjet and has been undergoing certification testing. But the type has failed to attract significant interest and the Ulyanovsk site, where Tu-204 airframer Aviastar is located, has recently become a focus of Sukhoi Superjet interiors work.
High-profile Russian businessman Alexander Lebedev, whose aviation interests include Red Wings, responded to the grounding order by proposing, via his social media feed, that 4 February should be declared a "national day of celebration for Boeing and Airbus".
Lebedev notes checks by Rosaviatsia and Rostransnadzor towards the end of 2012, and says the situation appears to have "changed drastically" in January.
He has previously encountered problems with airline regulators, after the German authorities suspended the operation of carrier Blue Wings - in which Lebedev's National Reserve Corporation held an interest - in 2009.
Blue Wings, an Airbus A320-family operator, resumed services for a few months before being grounded again in 2010.