The 10 rules of plane toilet etiquette

When you’ve gotta go, you’ve gotta go. But some people seem to have superpowered holding capacity, or maybe it’s just fear of what lies in store when they open the door of the aircraft toilet. The visit to the aircraft’s cabinet of curiosities is never something to look forward to, but it gets worse when some are out of action.

There are no specific rules about how many toilets an airline needs to provide on board.Credit: iStock

Earlier this month, a Qantas aircraft from Melbourne to Hong Kong took off with three of the five toilets in economy class inoperable. Passengers were messaged about 90 minutes before take-off, being told: “We sincerely apologise for the inconvenience and we know this is not the experience you expect from us.” There was no offer to rebook or get a refund.

How many toilets on an aircraft must be operable for it to fly?

Theoretically, zero, although you can imagine the stench from passengers. There is nothing in the flight rules. In Australia, the Civil Aviation Safety Authority publication General Operating and Flight Rules Plain English Guide makes only one mention of toilets, in relation to the non-smoking regulation. In the US, although the Federal Aviation Administration has a minimum equipment list, there’s nothing in the regulations that requires a minimum number of operating toilets.

In better news from Qantas, the airline revealed last week it would be putting an extra toilet on its new Airbus A321XLR planes, which will replace its short-haul Boeing 737s.

How do aircraft toilets work?

It’s a myth that waste in the toilet gets sucked out of the aircraft, though leaks can occur.Credit: iStock

Aircraft toilets operate on a vacuum system. When the toilet’s flush button is pressed, a valve opens and the vacuum sucks the waste in the bowl into a holding tank. Only a small amount of liquid sanitising solution is required to clean the bowl, which is a big advantage in an aircraft, where a conventional flush toilet system would need a huge quantity of water.

There are other advantages to a vacuum system over the standard gravity flush mechanism. The sewer line can use smaller diameter pipes, and the pipes can be routed sideways or even upwards because the vacuum system works in any direction. On the ground, the tank is emptied and the waste disposed of at a treatment facility.

While the system copes well with human waste and toilet paper, some things are never meant to go into an aircraft toilet, as passengers on an Air India flight discovered in early March. According to a CNN report, the flight from Chicago to New Delhi was several hours into its journey and over the Atlantic when passengers reported clogged toilets. Eventually, eight of 12 lavatories on board were “unserviceable”.

Due to restrictions on night landings at European airports, the Boeing 777-300ER was unable to continue its eastward journey and had no choice but to return to Chicago. Upon inspection, rags, articles of clothing and polythene bags had been stuffed into the toilets, causing blockages. Wipes, disposable nappies and paper hand towels are also common causes of blockages.

Can the toilet waste leak from an aircraft?

It has happened, although it’s rare. If waste seeps from the aircraft’s holding tank – most often from a faulty hose valve where the liquid is extracted – it would freeze as soon as it exited the skin of the aircraft because the average temperature at an aircraft’s cruise altitude is about minus 40 degrees. Then, when the aircraft descends into warmer air, the ice would thaw and eventually fall from the fuselage. Whatever hits the ground is mixed with blue toilet disinfectant and therefore it’s known as “blue ice”.

What people get up to in aircraft toilets

There’s the famous mile-high club, which must require yoga-like contortions given the dimensions of aircraft toilet cubicles. If this is on the agenda and it’s a twin-aisle aircraft, go for the mid-cabin toilets, which offer more headroom, and choose an Airbus, which have more spacious toilets than aboard comparable Boeings. Some of the smallest toilets are those aboard Boeing’s 737 MAX, measuring just 100 centimetres by 61 centimetres.

On an Air India flight from Delhi to Sydney several years ago, a fellow passenger repurposed the toilet as a bar. He locked himself in and consumed a decent amount of the duty-free liquor he had bought at the airport.

Returning to his seat in the row behind me, he became very chatty. Although he was docile and non-threatening, the crew zip-tied his wrists to the armrests, later removing him to the rear of the aircraft. When we landed in Sydney all on board had to remain seated for some time while security boarded the plane and removed him.

Plane toilet etiquette

• Barefoot in the bathroom is beyond gross. The same goes for socks. If you have a pair of free slippers from a hotel that’s fine, but abandon them when the flight is over.
• Shut the lid before flushing. It helps the vacuum clear the toilet bowl cleanly and efficiently. Also, it’s more pleasant for the next arrival.
• Don’t linger. It’s not a changing room, bathroom or make-up room. Do what you have to do and make it snappy – there are other people waiting.
• If there’s a queue and a parent with a young child is waiting, let them go first. When young kids need to go, they often need to go immediately. It will be more pleasant for everyone in the long run.
• Do wash your hands, and wipe down the bowl with your hand towel. Prepare the toilet for others as you would like to find it.
• Try to avoid using the toilet when meals are being served or collected. You might find yourself trapped waiting for the trolley to clear the aisle.
• If you’re not in an aisle seat and the person who is looks like they want to sleep, use the bathroom to avoid having to wake them up later.
• If there’s a mess in there, politely alert the crew.
• Don’t wait in the galley. It annoys the crew and they’ve got jobs to do.
• Even after you’ve used the toilet and washed your hands it’s a great idea to disinfect them again with hand sanitiser before handling food.