Unlocking Pilot and Crew Secret Codes and Phrases

To the untrained ear, the chatter between pilots and cabin crew sounds like a foreign language. Between the beeps of the public address system and the chime of the "fasten seatbelt" sign, a secret lexicon is being deployed. For every "welcome aboard" you hear, there are a dozen codes being whispered that you are not meant to understand.

From coded phrases for unruly passengers to international distress signals that flash across radar screens, here are the secret codes and phrases pilots and crew use—and what they really mean.