If you’ve ever used an airplane restroom, you’ve probably wondered—where does the waste go after you flush? While it might seem like a mystery that sparks some wild and scary guesses, the truth isn’t nearly as alarming. Human waste doesn’t get dropped from airplane vents like loot crates in PUBG. This is what a pilot explained to his TikTok followers. If you imagine waste falling from 30,000 feet, you’ve likely been influenced by a few too many Jim Carrey movies. The reality, as Pilot Garrett points out, is much simpler and, thankfully, more practical.
What a Pilot Says About Airplane Toilet Flushes
When you’re on a plane and need to use the restroom, have you ever wondered where the waste actually goes? Contrary to popular belief, flushing the airplane toilet doesn’t release waste over the population below. Instead, it travels through plumbing to sealed compartments at the back of the aircraft, where ground crew remove it upon landing. On a long-haul flight in a 747, toilets can be flushed more than a thousand times, producing over 320 gallons of waste—that’s quite a lot! This surprising fact has left many of Garrett’s TikTok followers stunned, with some even questioning how anyone could think that waste is dumped mid-flight.
One commenter wrote, “Are there really people who believe waste gets dumped out of the plane onto the population below? And if so, do these people vote?” Another expressed disbelief, saying, “I still can’t understand how people think it just gets dumped from the plane.” A third user asked, “Who even came up with the idea that it drops straight down?”
On the other hand, some people shared why they believed planes disposed of waste that way. One honest commenter said, “Since I was a kid, I thought pilots flushed waste over the sea. OMG.” Another added, “Thanks for clearing that up. Hopefully, now we can put this myth to rest.” A third person summed it up perfectly: “Ground crew definitely deserve a raise.”
How Science Ensures Safe Waste Handling on Airplanes
This brings us to an important question—how does the waste disposal process actually work on airplanes? Typically, airplane toilets use one of two systems. The first is a closed waste system, similar to a regular household toilet, which flushes water into an onboard sewage tank. The second is a vacuum waste system, which sucks the wastewater directly into the tank. When the plane is in flight, the vacuum system operates using the difference in air pressure between the outside of the aircraft and the cabin, creating a strong suction whenever a passenger flushes. Under normal circumstances, the ground crew handles the removal of sewage once the plane has landed.
The Early Innovation Behind Airplane Toilets
In 1975, James Kemper designed the first airplane toilet, featuring a nonstick bowl, ample Skychem chemicals, and powerful suction. When flushed, a trapdoor at the base opens, releasing the liquid and sucking everything away. The waste then travels through plumbing to sealed tanks at the rear of the aircraft, safely stored away from passengers until landing. On long flights, passengers might flush up to 1,000 times, generating around 230 gallons of sewage. After landing, specialized “honey trucks” are used to safely remove and dispose of the waste.
What Causes Blue Ice in Aircraft Waste Systems?
In cases of a malfunction, waste from an airplane toilet can leak from the tanks. This usually happens when there’s a crack in the drain tube or sewage tank, leading to what’s known as blue ice. Blue ice forms when the blue waste treatment fluid in the plane’s toilet freezes at the extremely low temperatures found at high altitudes. While it’s commonly believed that blue ice forms outside the aircraft, there are instances when chunks break off before landing.
When these chunks fall away, they typically melt and evaporate before reaching the ground. However, there are rare occasions when blue ice remains frozen even after entering the earth’s atmosphere and only melts upon contact with body heat. This was the case for a couple in Leicester, England, who found blue ice in their hair that began to melt and emitted a urine-like smell.
