During your average plane ride, you'll likely hear some sounds that might alarm you but are really nothing to worry about. If you hear a mechanical whirring, it could just be the pilot controlling the flaps or the landing gear, a high-pitched noise might just be the engines spinning, and a "ding" is likely just a passenger calling for a flight attendant. However, there is one sound that if you hear, you should be concerned.
Tommy Cimato, a flight attendant, shared what to look out for in a TikTok video. He first explained that when you hear a high-low chime, like a ding-dong, it is just a flight attendant trying to get a hold of another flight attendant, or the flight deck trying to reach them. However, he said that if you hear three of those in a row, there is an emergency on board.
While you should be a little worried in the extremely rare case you hear the triple chime, you don't need to totally freak out. A flight captain told USA Today that the three chimes could indicate a passenger with a medical problem that might cause the plane to be diverted, or that there is serious turbulence ahead and that the flight attendants should sit down and buckle up.
Whatever the cause of the triple chimes, it should be your clue to be very aware of your surroundings since something on your flight likely isn't going smoothly.