Russia's federal air transport authority, Rosaviatsia, is threatening to ground budget airline SkyExpress over extensive delays to the carrier's flights.

Every fourth flight is delayed by two to six hours, says the authority after it conducted a review into the carrier's operations, while the number of delayed flights has risen 2.5 times compared with last year.

Rosaviatsia says that almost half the fleet is undergoing planned maintenance, with just five out of the carrier's nine aircraft available, and that this is the primary reason for the chaos.

It adds: "The management of SkyExpress knew that such a situation might arise. But by [the airline's] own admission...measures to reduce proportionally the scheduled and charter flights were taken too late."

Rosaviatsia also says the airline was in "serious financial crisis" during the first quarter of this year - with unprofitable ticket sales, lower earnings and negative cash flow - and that this has "compounded" the situation.

SkyExpress has been handed a 24 July deadline to rectify the situation, the authority adds, and warned that it faces suspension of its operating certificate if it fails to comply with commitments.

Moscow-based SkyExpress, which uses a fleet of Boeing 737-300s and -500s, could not immediately be reached for comment.

Source: Air Transport Intelligence news