An Austrian Airlines Airbus A321-200, registration OE-LBE, was climbing out of Vienna’s runway 16 on flight OS-229 from Vienna (Austria) to Berlin (Germany) when the crew stopped the climb at about FL160, donned their oxygen masks, and decided to return to Vienna, reporting smoke in the cockpit.
About 19 minutes after takeoff, the plane safely landed on runway 11.
A passenger reported a sudden severe smell of burnt plastics, and the captain later revealed (audibly via his oxygen mask) that the smell was coming from a failed avionics blower fan.
The cabin crew acted professionally and calmly. While the aircraft was preparing to land, the odor dissipated, and the aircraft was picked up by emergency personnel.
According to the airline, the aircraft returned due to smoke in the cockpit, and the crew donned their oxygen masks.
The smoke was caused by a faulty fan. The passengers were rebooked on a later trip, and the aircraft used to carry them, OS-235, was upgraded to a Boeing 777.