A Rossiya Airbus A319-100, registration VQ-BAS performing flight FV-6413 from St. Petersburg to Ufa (Russia), was climbing through FL340 when the crew initiated an emergency descent due to indications of loss of cabin pressure. The aircraft returned to St. Petersburg for a safe landing about 45 minutes after departure.
A replacement A319-100 registration VQ-BCP reached Ufa with a delay of 2 hours.
The occurrence aircraft is still on the ground about 6 hours after landing back.