On 3 December 2017, an Embraer E190 en-route at FL310 was already turning back to Helsinki because of a burning smell in the flight deck when smoke in the cabin was followed by smoke in the flight deck. A MAYDAY was declared to ATC reporting “fire on board and their suggested diversion to Turku was accepted. The situation initially improved but worsened after landing prompting a precautionary emergency evacuation. The Investigation subsequently attributed the smoke to a malfunctioning air cycle machine. Issues with inaccessible cabin crew smoke hoods and with the conduct and aftermath of the evacuation were also identified.