11 Unique Airplane Facts You Probably Didn’t Know

Airplanes can get struck by lightning.

Planes are designed to be struck by lightning — and they are regularly hit. It’s estimated that lightning strikes each aircraft once a year — or once every 3,000 hours of flight time. Yet, lightning hasn’t brought down a plane since 1967, due to careful engineering that lets the electric charge of a lightning bolt run through the plane and out of it, typically without causing damage to the plane.

There is no safest seat on the plane.

The Federal Aviation Administration says there is no safest seat on the plane, though a TIME study of plane accidents found that the middle seats in the back of the plane had the lowest fatality rate in a crash. The research revealed that, during plane crashes, “the seats in the back third of the aircraft had a 32% fatality rate, compared with 39% in the middle third and 38% in the front third.”

However, there are so many variables at play that it’s impossible to know where to sit to survive a crash. Plus, plane crashes are incredibly rare.

Some airplanes have secret bedrooms for flight crew.

On long-haul flights, cabin crew can work up to 18-hour days. To help combat fatigue, some planes, like the Boeing 777 and 787 Dreamliners, are outfitted with tiny bedrooms where the flight crew can get a little shut-eye. The bedrooms are typically accessed via a hidden staircase that leads up to a small, low-ceilinged room with six to 10 beds, a bathroom, and sometimes in-flight entertainment.

The tires are designed not to pop on landing.

The tires on an airplane are designed to withstand incredible weight loads (38 tons!) and can hit the ground at 170 mph more than 500 times before ever needing to get a retread. Additionally, airplane tires are inflated to 200 psi, which is about six times the pressure used in a car tire. If an airplane does need new tires, ground crew simply jack up the plane like you would a car. If the tires fail during takeoff, pilots will abort the flight and land immediately for a safety inspection.

There's a reason why cabin crews dim the lights when a plane is landing.

When a plane lands at night, cabin crews will dim the interior lights. Why? In the unlikely event that the plane landing goes badly and passengers need to evacuate, their eyes will already be adjusted to the darkness. As pilot Chris Cooke explained to T+L: “Imagine being in an unfamiliar bright room filled with obstacles when someone turns off the lights and asks you to exit quickly.”

Similarly, flight attendants have passengers raise their window shades during landing, so they can see outside in an emergency and assess if one side of the plane is better for an evacuation.

You don’t need both engines to fly.

The idea of an engine giving out mid-flight sounds frightening, but every commercial airplane can safely fly with just one engine. Operating with half the engine power can make a plane less fuel-efficient and may reduce its range, but planes are designed and tested for such situations. Any plane scheduled on a long-distance route, especially those that fly over oceans or through uninhabited areas like the Arctic, must be certified by the FAA for Extended-range Twin-engine Operations (ETOPS), which is basically how long it can fly with one engine. The Boeing Dreamliner is certified for ETOPS-330, which means it can fly for 330 minutes (that’s five and a half hours) with just one engine.

In fact, most airplanes can fly for a surprisingly long distance with no engine at all, thanks to something called glide ratio. Due to careful aeronautical engineering, a Boeing 747 can glide 17,000 feet (just over three miles) for every 1,000 feet of altitude lost. This ratio gives the pilot more than enough time to get everyone safely to the ground.

There are ashtrays in the bathrooms for a reason.

The FAA banned smoking on planes in 2000, but eagle-eyed passengers know that airplane lavatories still have ashtrays in them. The reason is that airlines — and the people who design planes — figure that despite the no-smoking policy and myriad no-smoking signs prominently posted, at some point a smoker will decide to light up a cigarette on the plane. The hope is that if someone violates the smoking policy, they will do so in the relatively confined space of the bathroom and dispose of the cigarette butt in a safe place — the ashtray, not a trash can where it could theoretically cause a fire. If you do smoke in the bathroom, expect a massive fine.

That tiny hole in the airplane window has an important function.

It’s to regulate cabin pressure. Most airplane windows are made up of three panels of acrylic. The exterior window works as you would expect — keeping the elements out and maintaining cabin pressure. In the unlikely event that something happens to the exterior pane, the second pane acts as a fail-safe option. The tiny hole in the interior window, called a "bleed hole," is there to regulate air pressure so the middle pane remains intact and uncompromised until it is called into duty.

Airplane environments make food taste worse.

Airplane food has a bad reputation, but the food itself isn’t entirely to blame — the real fault lies with the plane. A 2015 Cornell University study found that the environment inside an airplane actually alters the way food and drink tastes — sweet items taste less sweet, while salty flavors are heightened. Low air pressure can further dull taste and smell, making everything on a plane seem bland. According to a study from the Fraunhofer Institute for Building Physics in Germany, it’s about 30% more difficult to detect sweet and salty tastes when you’re up in the air. Next time you fly, skip the meal, and maybe try a glass of tomato juice instead, a drink that tends to taste better in the air than on the ground.

Oxygen masks last for only 15 minutes.

The safety instructions on most flights include how to use the oxygen masks that are deployed when the plane experiences a sudden loss in cabin pressure. However, one thing the flight attendants don’t tell you is that oxygen masks have only about 15 minutes worth of oxygen. That sounds like a frighteningly short amount of time, but in reality, that should be more than sufficient. Remember, oxygen masks drop when the airplane cabin loses pressure, which means the plane is also losing altitude. A pilot will respond to that situation by donning an oxygen mask and moving the plane to an altitude below 10,000 feet, where passengers can simply breathe normally, no extra oxygen required. That rapid descent usually takes fewer than 15 minutes, meaning those oxygen masks have more than enough air to protect passengers.

Airplane trails are made up of water.

Those white lines that planes leave in the sky are simply trails of condensation, hence their technical name of “contrails.” Plane engines release water vapor as part of the combustion process. When that hot water vapor is pumped out of the exhaust and hits the cooler air of the upper atmosphere, it creates those puffy white lines in the sky. It’s basically the same reaction as when you see your breath when it’s cold outside.