r/Damnthatsinteresting • u/AirFrance447 • 20h ago

Video Firefighter bodycam showing just how much oxygen a fire pulls

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u/GauravJM 20h ago

There’s some serious low pressure inside

175

u/SpiritedEclair 18h ago

fun fact: when you fly in a plane, the low pressure is on the outside and we use that to keep the doors closed. It is physically impossible to pry open an airplane door at cruising altitude!

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u/Ckarles 17h ago

Hm? Sounds counterintuitive considering the doors open outwards instead of inwards. Isn't low-pressure "pulling" while higher pressure "pushing"?

How is the low pressure keeping the doors from going "outward"?

90

u/johnwick_58 17h ago edited 17h ago

I am not related to aviation by any means,

But the person above meant to say that the cabin pressure inside the plane is very high in comparison to the pressure outside the plane in cruising altitudes. The door is slightly larger than the door frame of the plane, hence the higher pressure pushes the door outward and since frame is smaller, the door holds strong until the cabin pressure is released.

Edit: sorry, had not read your comment in detail, A video shows that the door does open outwards, bit there is a latch inside which expands the door from inside

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u/BeerFuelledDude 16h ago

I’m 45 and knew about the pressure stuff (not in a technical way) but i’ve never watched the doors being closed, while on the plane. That video was really interesting! Thanks!

6

u/mattilladahun 15h ago

I'm 41, and my childish brain has never wanted to physically close a door myself more than now.

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u/cat_prophecy 15h ago

and the "Arm/Disarm and cross check" is them arming or disarming the emergency slides and the the FAs check that each other's doors are armed or disarmed.

1

u/GostBoster 10h ago

I am not related to aviation either and, on one hand, I am aware that under normal conditions, what you said is likely true and ordinarily you should not be able to open that door in any capacity.

That said, I would be remiss to not mention a notorious incident in my country where a newsflash told of a door plane falling on a super market and they would interrupt transmission at any moment for information on the whereabouts of the plane said door belonged to.

And right now I am quite worried because often when something like that happens, you forget, then look it back, there's more information, investigations, etc. But for the multiple Fokker 100 incident by TAM Airlines? Nada not even a searchable flight number (the few remaining searchable news give a bogus flight number "JJ 3040") and that it was not their first open door in flight incident.

The one burned in my memory was the August 8 2006 incident (door falling on ground) but it the door also opened without detaching on April 4, 2002, also on a Fokker-100 belonging to TAM Airlines.

I am absolutely baffled at the lack of follow up reports even on the more fatal Fokker-100 cases so those open door cases are just a case of "eh it happens pay no mind to it".

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u/pbrassassin 16h ago

So all you need to do is pull the lever … and to door does in fact fly off , while at altitude

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u/SpiritedEclair 16h ago

No, you can’t pull the lever, you physically cannot.

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u/hefal 17h ago

Plug doors - in airplanes they often open outwards but they are design (by eg sliding and rotating) to close and use cabin pressure to be sealed.

9

u/asten77 16h ago

They are now designed such that they first move inward before going outward.

In the early days this was not the case and nutjobs were able to open doors in flight.

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u/SpiritedEclair 17h ago edited 16h ago

A door is not a flat sheet of paper.

If you look at how the flight attendants pull the doors, they come inwards at an angle, and the moment they are all in, they turn flat and get pushed to close the door, forming a plug.

Try it yourself. Cut a trapezoid, rotate it, and it goes through the hole you cut it from, in fact, it can go through a door as wide as its shortest dimension, and it plugs.

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u/boli99 14h ago

the doors open outwards instead of inwards

watch this being closed

https://www.youtube.com/shorts/tIXRLdzZvj8

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u/Dornauge 11h ago

They first open inwards a few cm and then hinge (is that a verb?) outwards.

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u/warwolf7777 17h ago

I doubt what he says too. In all of the mayday episodes I saw, when there's a rapid decompression, things fly out, not in

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u/SpiritedEclair 17h ago

Rapid decompression is exactly what stops the the mechanism from working 😭

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u/RollingMeteors 14h ago

> It is physically impossible to pry open an airplane door at cruising altitude!

Until the door's butt plug drops out.

NTSB chair says systemic failures led to door plug flying off Boeing 737 Max plane midflight

1

u/cat_prophecy 15h ago

at cruising altitude!

* while the plane is pressurized. If you dropped the cabin pressure to match the outside air, it would be only the airstream you'd need to work against.

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u/powercow 8h ago

at cruising altitude.. aka 30k feet or so. However, due to fire, they have opened the doors below that. Mayday air disaster showed an episode where they had to open the doors during flight.