What happened
On May 17, 2012, an Airbus A320 operating within the Sofia FIR experienced a sudden decompression while cruising at flight level 370. Following the loss of cabin pressure, the flight crew attempted several procedures to restore pressure; however, these efforts were unsuccessful, necessitating an emergency descent.
During the descent, oxygen masks deployed throughout the cabin. Passengers reported seeing smoke and sparks originating from an oxygen generator. The generator became overheated and fell onto the cabin floor, where it ignited, producing flames and smoke. The cabin crew utilized onboard fire extinguishers to suppress the flames and prevent the fire from spreading. Upon landing, the continued presence of smoke in the cabin prompted the crew to perform an emergency evacuation of all passengers via the aircraft's emergency slides.
The investigation
The investigation into this serious incident was transferred to the Bulgarian Commission for Air Accident Investigation (KBWL) in 2012. The Polish State Commission for Aircraft Accident Investigation (PKBWL) noted that the Bulgarian authorities were unable to finalize the official report due to personnel changes within their commission.