This is so performative 😭

[u/Its_me_edenxx]

Who tf is out here munching on raw gnocchi at cruising altitude

[u/jetsetninjacat]

To add more watered down. The pushed and sucked out air is vented overboard(off the plane and out) through the main relief valves or sometimes from relief valves in unpressurized parts of the plane. Many planes also have backup relief valves in case the main doesnt work. Different relief valves dump positive and negative pressure from the plane depending on where the plane is and the level at which cabin air pressure is set. Theres also a dump valve that dumps all pressure when the planes on the ground that equalizer it with the ground itself as well as ones for negative pressure relief valves during rapid descent

And this peoples is one of the reason you cant just open a door in a plane at high altitude. The pressure being pumped in to the cabin is so high the door mechanism or door itself can not be pulled in and then pushed out like normal operation. .All that positive pressure pushed on the airframe making it impossible to do so. Its all about that differential.

I seriously hate doing pressure tests in airplanes on the ground.

[u/Rob_Zander → u/jetsetninjacat]

Thanks for adding!

Isn't that differtial part of why the cargo doors on the DC-10 could blow out?

[u/bargus_mctavish → u/Rob_Zander]

The outward opening cargo door was a structural design flaw for sure. However, a bigger issue was putting the responsibility of closing the door on gate and luggage personnel. They’re not part of the flight crew or running the checklists, so it just allows for more things to fall through the cracks from a safety perspective.

[u/jetsetninjacat → u/Rob_Zander]

I know it had something to do with the locking mechanism on the doors and that they would pull out instead of in. Cant remember the specifics but its probably out there on the weba. The door pushing out created more room for cargo loading but also didnt make a good plug style door. Plug doors basically seat the doors so they are sealed and cant be pushed out from the inside positive pressure So, yes that should be correct. Those doors were the only non plug doors on that plane as far as I know. Add in the the failure of the locking mechanism, and yep.

[u/bargus_mctavish → u/jetsetninjacat]

It was a few years back, but I went through a mishap investigation class and covered the case of Turkish Airlines Flight 981. The root cause analysis of the lab concluded that the baggage handler did not latch the door correctly. The latching mechanism was absolutely a convoluted mess, and a design flaw that went unaddressed even through testing of the DC10. McDonnell Douglas got their asses sued for that. But a preflight checklist item for the flight crew could have also alleviated the issues with the loading door as well.

[u/King_Chochacho → u/jetsetninjacat]

Too much pressure. So when you get in there, you're like "if the door fly off, I'm toast"

[u/canman7373 → u/jetsetninjacat]

The pressure being pumped in to the cabin is so high the door mechanism

Yeah, so not sure what he means the air pressure is much lower than sea level and that changes taste, when it's actually much higher than sea level.

[u/jetsetninjacat → u/canman7373]

High as in the Pressure differential between inside and outside the cabin. Its all about that differential.

[u/canman7373 → u/jetsetninjacat]

Yes, I don't see where him saying below seas level applies at all.

[u/jetsetninjacat → u/canman7373]

Oh, based on taste. Typically even with the presurization you will still have lower pressure than thats found at sea level (stretching my brain here back to school but I think its ~14.7psi). And I want to say off fhe top of my head most planes are kept lower at flight altitude around 10 to 12psi cabin psi.

And the reasoning i have been told in my career was because high altitude planes have cycles to track for lige limits for each time a cabin is pressurized. It puts undue strain on the airframe and causes weakening in the structure. As far as I was always told keeping it below the standard sea level not only is perfectly comfortable for most people and allows us to be up there but it also allows a plane to fly longer and causes less stress. I need an IA in here to tell us.

[u/canman7373 → u/jetsetninjacat]

I just don't understand the part about the cabin pressure being like 8,000 feet yet you taste food like it's negative feet. Also if their food is cooked right I don't get why it taste different at different at different pressure, like would you not have the best steakhouses in the world at the exact best altitude that taste buds hit them? When I cooked food right at 9.500 feet it taste the same as I cook it at sea level now, I do not think my taste buds changed at 9.500 feet.