If you fly, you’re likely familiar with the ding sound made when the “fasten seat belt” sign turns off, signaling you’re free to move about the cabin. But discerning ears may have noticed the ding, or chime, occurs at other times during the flight, too: Sometimes it’s a single chime long before the seat belt sign turns off, and sometimes it’s a two-toned rhythm, with a high-pitched chime followed by a low one. Other times, the sound is more like a “boing.”
“On our Airbus aircraft you’ll hear the ‘boing’ sound shortly after take-off ― this sound lets crew know that the landing gear is being retracted. The second boing is usually when the seat belt sign is switched off,” the airline explained in a blog post last year.
Qantas uses a single chime to alert crew when a passenger is asking for assistance at their seat. A high-low chime combination is the sound of the crew calling each other on their in-flight phone system. Three low chimes in a row signals an urgent warning from the captain, like heavy turbulence ahead.
However, that’s just Qantas. There’s no hard-and-fast rule for these sounds because each airline customizes its sound system differently, Airbus spokeswoman Kara Evanko told HuffPost.
United Airlines, for example, sounds a single chime when a passenger calls for assistance and when the fasten seat belt sign turns on. A ding-dong sound means pilots and flight attendants are calling each other on the inflight call system, spokesman Jonathan Guerin told HuffPost.
On other airlines, a chime might indicate the plane has reached 10,000 feet and it’s safe to use electronic devices, commercial pilot Patrick Smith told HuffPost. It could also mean the plane is landing soon and crew should start cleaning up the cabin. Other sounds usually come from the intercom system that cabin crew share with the cockpit.
“Think of it as a language between the pilots and flight attendants,” Southwest Airlines spokeswoman Cindy Hermosillo told HuffPost. On Southwest planes, a single chime means the seat belt sign has been turned off. The airline also uses high chimes, low chimes and a high-low chime combination for communication in the cabin, but declined to specify what each sound means, citing security.
Likewise, an American Airlines spokesman said he couldn’t share information about the airline’s “internal mechanisms for communication between our flight attendants and pilots.”
While the true meaning of these sounds may remain secret on some carriers, it’s always helpful to learn about life in the sky if you’re a nervous flier. Next time you hear a chime on a flight, you can rest assured it’s typical crew talk.