Many people are convinced that when they flush an airport lavatory, that the contents drop on the people below!
This is fueled by the legendary stories about “blue ice” tearing through roofs across the world. “Blue ice” is the mix of sewage material and blue liquid disinfectant that freezes because of the plane’s altitude.
One chunk in London tore a large hole in the roof of a Unitrainn Church in London, and is reprtedly one reason for the building’s demolition! Earlier this year, a guy in the UK lost part of his conservatory roof to Blue Ice. In the TV series Big Bang Theory, Leslie Winkle says to Leonard Hofstadter: So, I heard your relationship with Penny crashed to the ground like blue ice falling out of an airplane lavatory. Check out the Mythbusters episode on “Blue Ice”.
The reality is that airlines are not allowed to dump their waste tanks in mid-flight. The current Vacuum Toilet system , designed by James Kemper in 1974 and installed into a Boeing in 1982 does not allow this to happen. In an aeroplane toilet, strong suction and very slick teflon like walls pull human waste away using only a very small quantity of water (saving on weight and space). When you press the flush button, the pneumatic vacuum at the bottom of the bowl sucks the contents into a large holding tank. At the end of a flight, the contents are sucked into a tanker at the airport and then dumped.
There have been incidents where excrement has been released accidently. On three Boeing 727s, waste from a leaking toilet hit the rear mounted engine, causing a power loss. The planes landed safely using their other two engines. The incidents took place in 1974, 1985 and 1990 and were linked to incorrect servicing of the toilets.
And no, it is not possible to get stuck in the toilet because of the strong suction.