Waiting for the seatbelt sign to be turned off is the first thing passengers do when a plane is taking off.
However, it can also mean something else entirely depending on how it is lit up.
A flight attendant recently revealed that if any travellers see the sign is flashing during take off or landing it could mean something else entirely.
The true meaning is somewhat terrifying to realise.
Annie Strand, a cabin crew member, wrote on online forum Quora what it actually means.
She commented: “This means the situation is so severe that the pilots don’t even have the time to inform us that we’re doing a safety landing (A nicer word for evacuation or emergency).
“If I see this, it means that we’re approximately 30 seconds of impacting with the ground, and who knows what happens next?
“In that 30 seconds I have to put all my fear of dying aside, and yell ‘Bend down’ as if my life depended on it.”
It’s not the only terrifying code that could reveal something sinister onboard.
Pilots have a secret way of warning a hijacking is taking place.
A distress code of 7500 is sent through an electronic device called a transponder to signals any unlawful interference.
Called squawking, it is a silent signal to avoid alerting the hijacker.
