Tatarstan Air (Kazan International) will be grounded effective December 31. In its directive, Russia's Federal Air Transport Agency (Rosaviatsia) calls for the airline's Air Operators Certificate (AOC) to be revoked for “noncompliance with Russia's airline certification requirements, violations of established norms of flying hours, working and relaxation time” among other reasons. The move follows the recent crash of a Tatarstan Air B737-500 at Kazan International which claimed the lives of all onboard.