https://consumerist.com/2017/10/30/united-plane-makes-emergency-landing-due-to-smoke-in-the-galley/

Smoke in the cabin of a passenger airplane is a scary prospect. That’s why a plane heading from Munich, Germany to Washington Dulles International Airport made an emergency landing at Boston’s Logan Airport instead: There was smoke pouring from the plane’s galley… which may or may not have actually been caused by a fire.

The plane was diverted to land at Logan, where emergency crews arrived to look for the source of the smoke. What they didn’t do was deplane passengers, who waited until after airport firefighters had checked out the galley before departing the plane.