Pilots and flight attendants often communicate with each other using the radio tannoy, meaning passengers can hear what they are saying.
Cabin crew will use code words as a way to discretely get their message across.
And now the meaning behind one of these words has been revealed – and passengers might be horrified to learn the truth.
In a Reddit thread, anyone who worked for an airlines was asked to reveal secrets passengers don’t know.
Flight secrets revealed: One former cabin crew member has revealed the meaning behind one code word
One of these items were always called HR on the radios. HR was an abbreviation for ‘Human Remains’
One person, ‘mrmiguez’, claimed to be a ram agent for a major American airline.
He revealed the meaning behind the code “HR”, and said: “A lot of freight gets shipped on commercial flights.
“One of these items were always called HR on the radios. HR was an abbreviation for ‘Human Remains’.
“Some people die far away from where they want to get buried. They’re packed in wood-framed boxes, so you would never know what was inside except by the strange shape of them.”
Flight secrets revealed: One cabin crew member has revealed ‘HR’ means human remains are onboard
Another poster commented on his revelation and said: “I did the same job. Had one that was HUGE one time. Took three of us cramped in the bin to get him situated.”
Meanings behind certain codewords are not the only flight secret to be revealed this week.
Many passengers might not have noticed it, but there’s a tiny yellow hook installed on a plane’s wing that could save your life.
Planes are equipped with an intricate system of safety features in the event of an emergency.
Flight secrets revealed: Passengers may not notice the code words cabin crew use to communicate
Flight secrets revealed: Cabin crew make lots of announcements before and during flights using codes
Some features like seat belts and your under-seat life vest are hard to miss.
But other crucial safety elements go unnoticed by many passengers.
One of the tools installed on planes that can help to save your life in the event of an emergency is almost too tiny to spot.
Wing hooks, usually yellow, are built onto each wing of the aircraft.