MIAMI —Russian carrier Transaero Airlines’ air operator certificate (AOC) will be canceled from October 26, according to a statement issued by Russia’s Federal Air Transport Agency (Rosaviatsia).

The agency performed an unscheduled audit between Oct. 6 and Oct. 20, finding that the airline “is unable to service and repay its debt, as well as fund its operations. That does not meet certification requirements of Federal Aviation Regulations (FAR). The struggling carrier had previously announced to cease operations on December 15, after experiencing financial problems. According to Russia’s Sberbank president Herman Gref, Transaero’s the debt of the airline is estimated to be RUB250 billion (US$4 billion).

Last September, Aeroflot planned to acquire Transaero, but the parties did not reach an agreement on the purchase of 75% of the stake plus one share of Russia’s second largest carrier within the deadline stipulated in the tender offer.

The day before the announcement of Transaero’s AOC decision, it was reported that Vladislav Filev, CEO of S7 Airlines,  acquired 51% of the stake in Transaero. The new shareholders will attempt to find a feasible financial solution. However, according to an early morning report by Reuters, the solution seems not to be viable.

Russian air transport is experiencing one of the worst crisis in its history as the market has been hit by the slump in oil prices, spiking a strong drop in purchasing power in 15 years, while the rouble has also seen its value to plunge, which caused fuel and aircraft leasing rates to rise.