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I am not a pilot so please forgive any misuse of aviation terminology; I'm merely a person who is working hard to overcome a sudden and intense fear of flying.

While working through a course to overcome this issue, the topic of emergency descents came up. I learned the purpose of these and the actions the captain / copilot must take, but the experience of the passengers was not discussed.

If a commercial jet is at 40,000 feet and experiences rapid depressurization, and the captain decides to make an emergency descent to 10,000 feet, what does this feel like for the passengers? Is it like being on a rollercoaster with a 30,000-foot drop instead of the typical 100-foot? In other words, do passengers experience freefall / weightlessness?

Do unbuckled passengers go flying all over the cabin? Is all unfastened material thrown across the cabin? What happens to crew who cannot make it to a seat fast enough? How common are these rapid descents in commercial flying?

I imagine this is probably the most terrifying experience a person can have, if it's anything like plummeting like a meteor.

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  • $\begingroup$ Emergency descents were one of the more fun maneuvers during training, might have a different view of them as a passenger though. Unless the aircraft is on fire, "emergency descents aren't that steep. The pilot has about 15 minutes to get down to thicker air before the passengers oxygen runs out. $\endgroup$ – Ron Beyer Feb 12 at 2:26
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No nothing like that. If there was what is usually called "explosive" decompression, like a window blowing out, there will be a loud BANG, maybe a short howling sound as air rushes out, possibly fog will form in the cabin, and you will feel the air pressure in your head trying to get out until it equalizes. It might make your ear drums hurt until it does. The air will be chilled by the temperature drop caused by the pressure drop.

The big surprise is you can't feel the "thin" air when you breathe (you'd have to be exerting yourself - just sitting still, you can't tell). The masks drop and at that altitude you have maybe 15 seconds to get one on before you pass out.

At any rate, explosive decompressions are pretty rare and emer descents are usually triggered by more gradual situations, like a slow loss of cabin pressure, or a windshield that suddenly cracks (although with several laminations and it normally won't fail totally - still, it'll scare the flight deck crew pretty good).

As far as the plane goes, you'll notice the thrust going to idle, the airplane decelerating temporarily, and you may feel the sensation of the nose pitching down to maintain speed, maybe a slight cresting-a-hill-in-a-car reduction in G sensation momentarily, but that's about it. Nobody floating around the cabin.

When the capt gives the command for emergency descent, whatever the reason, (after they get their masks on and establish communication with each other) the procedure is to pull the thrust to idle right away, spin the altitude select knob for the autopilot to a lower altitude, and set the autopilot to "speed" mode, which tells the autopilot to pitch the nose to maintain airspeed (if the pilot were to shove the nose over manually, it could result in going zero or negative G and making people float around, but the procedure is usually done using the autopilot, which does the pitch over gradually, so that shouldn't happen).

The autopilot will start to pitch the nose over to keep the speed up since the thrust was taken away, so there will be the initial deceleration from pulling power, then a very gradual acceleration in the descent. If the plane has "flight spoilers", the kind that can be extended in flight, they will also be set fully out, so there'll be the rumble from that, and possibly the capt may drop the landing gear to increase the descent rate, depending on the speed and the airplane.

As it starts to pitch over the pilot will dial the speed to maxmimum operating speed if he/she is confident there is no major structural damage. If unsure, you are supposed to stay at the speed you were at when whatever happened happened. The most unpleasant part will probably be the noise level in the cabin if there was a rupture of some kind. Even if there is nothing blown out, when descending at maximum speed the overall noise level is pretty high, a lot louder than cruise.

They'll be heading for 10000 ft and it'll only take a couple of minutes, so it'll be over pretty fast.

Thing to keep in mind about those plastic cabin windows (the structural outer panel, not the one next to you with the tiny vent holes at the bottom). If it's 8" x 10", there is over 600 lbs pushing on it with the cabin pumped up to 8 psi. Sounds dicey. But the acrylic plastic is very thick and the window actually has roughly the same strength as the (much thinner) adjacent sheet metal, so it's actually subjected to a fraction of the stress it's able to take.

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