The truth behind a popular aviation urban myth known as 'blue ice' has been revealed.
Most of us will have heard the weird rumour that every-time you go to the toilet on aeroplane a mysterious flap opens up underneath the fuselage and expels your waste into the atmosphere – just like how older train carriages will dump human waste onto the tracks.
This is, of course, not actually true, although it didn't stop people making up stories about a person who died after being unwittingly impaled by a flying urine icicle.
While the myth of flying urine and faeces isn't actually real, there is a similarly grim quirk which occurs in airplane toilets which will certainly make you shudder.
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Enter blue ice.
What is 'blue ice'?
When a person goes to the toilet at 35,000ft their waste is stored in the aircraft's septic tank, which is then emptied upon arrival at the airport.
However, every now and again waste can leak from the plane's septic tank, the sewage - which is mixed with blue disinfectant - escapes to the outside of the aircraft.
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With temperatures reaching as low as –60 degrees°C, the runaway waste then freezes to the underside of the aircraft.
When the plane descends to its destination, chunks of the ice then fall off the aircraft to the ground.
Has anyone ever been hit by 'blue ice' falling from an aircraft?
Fortunately incidents of falling blue ice are pretty rare, however there have been a number of unlucky souls who've either been injured or had property damaged by falling faeces over the years.
In 2024, a house in New Jersey suffered extensive damage after huge chunks of ice believed to be biowaste crashed through the roof.
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According to homeowners Paul and Fabi Gomez, the chunk of ice had crashed through the third floor and damaged the second floor ceiling, however no one was injured in the incident (via NJ.com).
A similar incident occurred in the UK in 2018, when chunks of ice crashed through the roof of a home in Bristol.
There have also been cases of people supposedly being injured by frozen biowaste.
In December 2015, an elderly woman was left with injured an injured shoulder after a 50 kg blue ice chunk came through her ceiling in India.
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However, you don't need to spend the rest of your days sleeping with one eye open or looking up to the sky in fear every time you hear a plane go overhead.
The Civil Aviation Authority classifies the risk of falling ice to be 'extremely low', with just 25 cases reported a year, compared to an average of 2.5 million flights which travel over the UK each year (via Heathrow Airport).
Brenna Cooper