By Simon Hradecky, created Sunday, Apr 11th 2021 21:12Z, last updated Tuesday, Apr 13th 2021 17:56Z

An Azur Air Boeing 737-800, registration VP-BIR performing flight ZF-344 from Sochi to St. Petersburg (Russia) with 190 passengers and 8 crew, was climbing through about 12500 feet out of Sochi's runway 24 when the passenger oxygen masks deployed due to the cabin not pressurizing. The crew descended the aircraft to 10,000 feet, burned off fuel and returned to Sochi for a safe landing on runway 06 about 90 minutes after departure.

On Apr 13th 2021 Rosaviatsia reported the aircraft was climbing out of Sochi when the crew received an alarm indicating "unsealing of the cabin". The crew descended the aircraft, burned off fuel and returned to Sochi.