Secret Airline Codes

If you don’t pop in your noise-canceling headphones the moment you take your seat on a flight, you’ll eventually hear a familiar sound: a “ping,” used by the crew to communicate with passengers. That non-threatening sound signals when you should stay seated and when you’re free to get up, for example. But sometimes those sounds aren’t meant for the customers. As People reports, airline crews use the chimes as a Morse code of sorts to alert each other to issues big and small.

Qantas Airways sh...