What happened
On December 23, 2024, an Airbus A220-300 flying from Bucharest Otopeni Airport to Zurich International Airport encountered a series of critical inflight emergencies while traversing Austrian airspace. At approximately 16:32 UTC, the flight crew observed EICAS advisory messages indicating a left engine fault and oil debris levels exceeding limits. Shortly thereafter, the crew reported engine vibration and a loud bang heard within the passenger cabin.
By 16:34 UTC, smoke was detected in both the cockpit and the passenger cabin. The flight crew donned oxygen masks, and a master warning indicated smoke in the lavatory alongside a drop in left engine oil pressure. The pilot declared a MAYDAY at 16:34 UTC, requesting an immediate diversion to Graz Airport (LOWG). Following the detection of the engine issues, the crew successfully shut down the left engine.
The aircraft landed on runway 34C at 16:53 UTC with the left engine inoperative. After coming to a full stop, the crew shut down the right engine and initiated an emergency evacuation at 16:55 UTC. The evacuation was carried out using four emergency exits, including the forward left door and both overwing exits.
The investigation
The Austrian Federal Safety Investigation Authority (SUB) is conducting an investigation into the occurrence. Investigators have analyzed data from the flight data recorder (FDR), cockpit voice recorder (CVR), and the aircraft health management system (AHMS), as well as radar and meteorological data.
Substantial focus is being placed on the engine's mechanical state, specifically the reported oil debris and vibration. The investigation is also examining the engine's internal components and the effectiveness of the emergency evacuation. Additionally, authorities are reviewing the use of protective breathing equipment (PBE) by the cabin crew and investigating why certain aircraft doors were not utilized during the evacuation process.