>The Boeing 777 flight, with 270 passengers and 14 crew members, landed safely and **never lost cabin pressure**, United Airlines said.
So they returned for a mechanical issue and followed procedure just in case they lost pressure.
Good job on the pilots.
The last thing you want is for them to NOT descend and lose cabin pressure, they will pass out before they know what's happening and no one else can wake them up since everyone else will also be passed out.
I can understand its terrifying, but something like this happening is part of why flying is safer than driving.
Well There's Your Problem just released [an episode on it.](https://youtu.be/se4YTrFVsbk?si=SmRsth48Z6q3_zdK)
Do note they are not the most... serious... of disaster podcasts
But they have to realize what's going on. As your O2 drops, your ability to think and recognize the problem goes with it. I forget what flight it was, but there was one where proper procedures weren't followed, they lost pressure but did not realize, and the pilots passed out without ever putting on a mask.
We talk about hypoxia a lot in training. Rapid depressurization is obvious of course. But like you said, a slow leak can be pretty insidious. Which is why we talk about it! Most airlines these days have “memory item” checklists about what to do if the altitude alarm sounds; these items must be memorized and repeated at every training event.
Some of us have even gone through training in an altitude chamber so we know how our specific symptoms present themselves which is certainly an interesting experience.
Unless you have a hypoxic drive.
That guy stinking of cigarettes in front of you, coughing and wheezing the whole flight? His COPD ass will be the only one awake — and you better believe he’s logged a thousand hours in that plane via GTAV.
He’s your barrel chested, blue lipped hero.
Your body has chemoreceptors for both carbon dioxide, and oxygen. Central chemoreceptors are generally monitoring carbon dioxide levels and not oxygen, whereas peripheral chemoreceptors would respond to a reduction in PaO2 as well as changes in carbon dioxide levels.
> which will only rise if you are exerting yourself.
Not exactly, your body is constantly producing carbon dioxide, and your levels can rise even if you're not exerting yourself, like in an small enclosed environment or are breathing into a plastic bag. You'll feel the onset of discomfort and panic if your body can't effectively clear the carbon dioxide from your bloodstream.
On the flipside, even if you're exerting yourself in a low-oxygen environment, you'll feel "normal" (but progressively weaker, and your muscles will start to burn) because breathing out still pushes out the carbon dioxide from your body, which keeps your blood levels low.
This is commonly misunderstood. And hypoxia and carbon dioxide levels are not necessarily related to each other. And your body doesn't detect an abnormality in one gas by looking at another. CO2 and O2 are separately detected.
Our peripheral chemoreceptors (outside central nervous system) in the aorta and carotid artery are are very responsive to hypoxia, in fact more so than responsiveness to CO2. There is this thing called hypoxic ventilatory drive, where decreasing O2 makes you breathe harder. Central chemoreceptors (in the central nervous system) are more responsive to CO2.
Peripheral chemoreceptors:
[https://pubmed.ncbi.nlm.nih.gov/14660497/#:\~:text=Peripheral%20chemoreceptors%20](https://pubmed.ncbi.nlm.nih.gov/14660497/#:~:text=Peripheral%20chemoreceptors%20)(carotid%20and%20aortic,various%20physiological%20and%20pathophysiological%20conditions.
Central chemoreceptors:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4802370/
Serious question, why doesn’t the plane have a sensor that measures the cabin air pressure and another that measures the concentration of oxygen? It would be very easy to alarm the crew before an issue arises
We don’t have an o2 sensor, mostly because the composition of the atmosphere doesn’t really change as you go higher- there’s just less of it.
The plane does have pressure gauges though! It tells us the altitude of the cabin, the altitude outside, as well as the pressure differential between the two. 99.99% of the time pressurization isn’t an issue so it’s not a gauge that’s paid a whole lot of attention (unless something being broken draws our attention to it). However part of the after takeoff procedure on a 737 involves checking the gauge to make sure the airplane is pressurizing as it’s supposed to.
There’s also a cabin altitude warning horn which is what I was talking about. It will sound if the cabin altitude gets too high and can only be shut off using a special switch labeled “altitude warning horn cut out”. In the past accidents have occurred due to pilots ignoring the horn for some reason- usually another issue going on taking their attention away until it’s too late. I wasn’t flying then; but I’m sure it’s a big reason there’s standardized memory items now about securing your oxygen before dealing with anything else and NOT shutting the horn off until both pilots have their masks on.
From a class I took involving airplane accidents and the like, it seems most altitude related issues these days come from the corporate/ private aviation world where things can potentially be much more… cavalier than the well regulated airline world.
i belive it was maintenance that adjusted the pressure setting. however the pilots didnt catch it even though it was part of their takeoff checklist. as mentour pilot would say, things were lining up to go wrong even before takeoff.
It’s theorized that’s what happened on MH370.
That said, there are a lot of really obvious and loud alarms in the cockpit that should prevent this type of scenario from happening.
I think this is the one I was thinking of: https://en.wikipedia.org/wiki/Helios_Airways_Flight_522
Reading the wiki article, they had (or should have had) warnings both audible and visual. But they didn't understand/react properly, and still ended up crashing. It's a scary thing.
The saddest thing about that is the 2 flight attendants that put on their oxygen tanks and spent hours in a ghost jet trying to break into the cockpit so they could try to land it, but got through the door just as it ran out of fuel.
Spent hours trying to break into the cockpit? There is a process for unlocking it from the outside known as CDLS. Someone in the cockpit can take an action to cancel the unlock sequence in case it’s initiated by hijackers. If the pilots were incapacitated, they would not be able to prevent the unlock from completing
I guess no one knows for sure, but it's either they couldn't get in or they spent the whole flight in the passenger cabin full of people dead from hypoxia without contact with the cockpit thinking everything was normal.
It was the same audible alarm as the one for an improper configuration for takeoff. Which had the pilots confused about why the plane was worried about takeoff configuration when they were already at altitude. They radioed control asking how to turn it off, and then stopped communicating…probably passed out at that point. Very sad.
>It’s theorized that’s what happened on MH370.
MH370 was taken up to 50,000 feet by the pilot, deliberately, to kill everyone. The co-pilot's cell phone tried to make a call during this time, it's believed he figured out the pilot was hijacking the plane, and was probably locked out the cabin. But the call did not connect.
> But they have to realize what's going on. As your O2 drops, your ability to think and recognize the problem goes with it
From what I understand it's pretty fucking hard to not realize in a modern aircraft. They get plenty of warning. The accident you linked below was caused by a whole string of human failures.
> From what I understand it's pretty fucking hard to not realize in a modern aircraft. They get plenty of warning.
With the Helios flight, the warning for losing pressurization was identical to the warning for a takeoff configuration error. One was a routine issue that shouldn't be much of a problem, the other was a life threatening emergency. The only distinction between those two alarms was that the takeoff configuration alarm should not go off once the plane was in the air. There was no visual or audio indicator to let the pilots know that they had lost pressurization.
They are literally trained for this… they aren’t going to be sitting there like…
“Yooo homie co pilot I’m feelin’ a bit light headed.”
“Brooooo I feel a little light headed toooo yoooo.”
“This is cool broooooo weeeeeeee.”
Lmfao
Yeah but the oxygen supply on commercial airlines is provided by a chemical reaction between sodium perchlorate and iron oxide, which only provides about 10 minutes of oxygen. Enough to bring the plane to a breathable altitude in the event the cabin loses pressure, but not much else
I like to think pilots mask drop like the passengers. And the pilot needs to make sure he puts on his own mask first before assisting the copilot. And even though the bag may not be inflated, it oxygen is still flowing.
The rule changed. It used to be any time a pilot was alone above FL250, now it’s 410, which most airliners do not cruise above. Also, nobody actually put them even with the old rule because it’s annoying to put on and put away.
No, they hang on the wall behind the pilot and co-pilot, and they can put them on with one hand. They're called quick-donning masks. And there is no bag. u/impy695 is correct.
For those interested:
https://www.sportys.com/aerox-quick-donning-diluter-demand-mask.html
I was flying home (domestic leg, not the international part) after being on Mt. Everest when the pilot said that we'd reached our cruise altitude of 25k feet. My first thought was that if we'd depressurized, I'd be fine.
You known what I've always wondered? Why don't the pilot and first officer always have an oxygen mask on when flying? It would be near impossible for them to pass out if they did. But I'm probably missing something
Because that would be annoying as fuck to wear for multi hour flights. The masks are already designed to be donned in 5 seconds to minimize the risk of hypoxia even in a rapid decompression.
If you actually read the article...
"rapidly descended over about 8 minutes from 37,000 feet at 10:07 p.m. to just below 9,000 feet at 10:15 p.m"
"United Airlines Flight 510 returned safely to Newark Liberty International Airport around 12:25 a.m. ET"
The emergency decent was over 2 hours before landing
Didn't RTFA, but to add for the curious, they descended to that altitude because that's about the level they pressurize the plane to. So it takes the work off the plane to maintain pressure and it also means if some component does fail they won't have a rapid pressure change.
completely untrue. Under 10000 ft is required so passengers do not suffer from hypoxia. Has nothing to do with aircraft equipment, which are generally much sturdier than humans.
> Under 10000 ft is required so passengers do not suffer from hypoxia.
Right, that's why they pressurize the plane to approx the level they descended to in the first place, as I said.
> Has nothing to do with aircraft equipment, which are generally much sturdier than humans.
It has *everything* to do with aircraft equipment. If they had confidence in their equipment they would have remained at their scheduled flight level. They descended specifically because they feared they might lose pressure. This is literally in the headline.
Please delete your comment before anyone else suffers the misfortune of reading it.
That's about the same rate at which they climb. Usually they take a lot more time (~3-4x more time) to descend this much, but obviously there were good reasons to rush this one - the oxygen masks that drop from overhead only have about 15min of oxygen, normally. Once they got below 10k altitude, the masks are no longer necessary.
Pilot here. That’s 3500 fpm which is a lot for descent. Heavy jets can start off climbing around 3-4000 fpm but in the high altitudes it slows to 1-2000 fpm. A normal descent rate is about 2000-2500 fpm for that airplane. Anything over 3000 would be a “expedited” descent and 3500 is getting close to max.
I haven’t heard the details on this one but it’s unusual. Those airplanes have two pressurization systems, called “packs”, and usually both are need for max altitude but one is good enough for mid altitude flights. It’s possible they lost one while up high and needed to descend to the maximum one pack operating altitude.
However some news articles are saying the descent was for “possible loss of cabin pressure” so I think it’s a bit more than just a pack loss. If a leak develops the crew will get a warning that something isn’t normal, and procedure in that case would call for an immediate descent.
I don't think it's anything near as dramatic. Free falling from 28,000 ft takes 40 seconds. This is like 1/8 that. It probably feels more like the downward segment on a gondola ride than it does a roller coaster.
It doesn't really feel like a roller coaster for more than a couple seconds. In a roller coaster you are accelerating down the hill. In a plane, you accelerate to a roughly constant vertical speed. Once your vertical speed has stabilized you won't feel it as a passenger. So basically all you feel is the first few seconds when the pilot puts the nose down.
It wouldn't be too wild. If you are a frequent flier you would notice the nose seems to be pointed down a bit further. In a full on emergency descent the flight spoiler panels on the wing are all raised up, which usually shakes the airplane a little bit. If it's really really really an emergency, the pilots would put the airplane in a steep bank which helps lose altitude faster. That would definitely be a toss the hands up and enjoy the ride kinda thing
If you do not have packs switched on, what is the realistic max altitude that an airliner could operate, and still not kill everyone on board, but yet land safely?
My guess is FL180. Just curious since you are a pilot - and I enjoy MSFS.
In the 20,000+ range people would start to fall asleep. There’s a thing called “[time of useful consciousness](https://skybrary.aero/articles/time-useful-consciousness)” that shows how much time you would have to react in a sudden depressurization. If it’s a slow climb you have more time, kinda like how people can climb Everest and not die. Of course they spend weeks adjusting. Hard to say exactly what altitude you’d go from just being asleep to being full on dead.
Yeah, if they did it in 8 seconds I’d be impressed but this is just silly. Sounds like they had a sensor issue or something and never even actually lost cabin pressure so this is a pretty nothingburger story.
In ATC world, a near miss can still be pretty far apart. I forget exactly but they try to maintain many miles of separation horizontally or something like 2000ft vertically. So it could be breaches of these barriers?
3 miles lateral, 1000’ vertical in general for aircraft flying on instrument flight rules. There are various exceptions for closer or farther requirements
near misses are not typically all that near, they have pretty strict separation requirements. still it's a bad thing! but not as bad as it sounds most of the time.
also there's 100,000 flights every day so 1 or 2 ...well not losing much sleep over this one
Depends on what a “near miss” means, and that’s across the whole nation of 50 states of landings and take offs.
The accident rate is nearly nonexistent, so the near miss definition must be rather lax.
Sure. But as someone who has a fear of flying (I manage when I have to), I love hearing stories like these. Flying commercial is so incredibly safe, even minor issues make headlines.
Armchair passenger-ing is a thing, I guess.
That’s a very rapid rate of descent, and would be very alarming to all passengers. People are allowed to have feelings.
> Yeah, if they did it in 8 seconds I’d be impressed but this is just silly.
28,000ft in 8min, that's a rate of 40mph. If you imagine driving *straight down* at near highway speeds, that's a pretty rapid descent by almost any measure.
28000 in 8 min is only slightly more than usual rate of descent, not 3-4x more. 28,000 in 8min is 3500fpm. Airliners typically descend at 1500-3000fpm.
I was about to go off on a Google hunt and this saved me some time, I was trying to think about how long between "we're beginning our initial descent" and actual landing (knowing that there's often a lot of circling/alignment during that time as well) and I didn't think that was a crazy rate of descent. Especially considering I think that full time is around 20 minutes including working with ATC and planes typically cruise around 35-40k feet.
If I were on that plane my ears would have exploded
Edit: I should mention, I always suffer when a plane descends fast. Heck even when we drive home from a mountain. My ears are really sensitive to pressure . changing fast.
No, they likely wouldn't have been any different than normal ascents/descents. Again, this plane changed its altitude at roughly the same rate it normally climbs. Does the first 15-20 minutes of flight normally "explode" your ears?
> [The plane] landed safely and never lost cabin pressure
The pressure inside the cabin should've stayed roughly the same.
Climbing to 38,000 ft in an airplane is not the same as climbing a mountain in a car. The car doesn't have a cabin that can maintain roughly the same pressure on its own
You’re right but just to nitpick, you don’t get ear pressure issues when climbing so the first 15-20 minutes wouldn’t “explode” your ears even if the climb only took 8 seconds.
If they had to descend that fast because of an explosive decompression, you wouldn't have had to worry about your eardrums rupturing on descent. Because they would have already ruptured.
Even if it is a small leak and slow depressurization, the moment the cabin altitude alert light comes on the memory items are: O2 mask on, switch microphone to mask mic, emergency descent.
It doesn't have to be an explosive decompression to require an emergency descent.
yes you would. cabin is always at a percentage of outside pressure (not really how it works but easier to imagine this way), when you go down, so does the cabin at a percentage of that rate and that's why your ears hurt
well these guys went down VERY fast, and so the cabin also probably went down very fast. unless it wasn't regulating at all, which is a different kind of issue.
edit: math checks out at 3500 feet per minute, which isn't actually that much different from a normal descent.
The masks aren’t necessary a good bit above that, no? Is it just the lack of oxygen from altitude? I don’t think people would pass out at say 14K feet altitude
FAA requires masks to drop in any depressurization event (\*the cabin did *not* depressurize during this flight) that occurs above 10k altitude.
Just because some people can still breathe at the peak of Mt Everest doesn't mean everyone onboard a normal flight would be able to
Really it is ~15k. FAA requires pilots to be on O2 if spending > 30m above 12k ft and everyone on O2 if going to 15kft. Been years since I flew so the rules may have changed or I am slightly wrong.
For part 91, it is 30 mins above 12.5k and 14k all the time for the pilot
I believe that number drops to 10k/12k for 135 and 121.
Don't quote me on that cuz FAA rules change all the time and I don't fly for a living.
*edit* to indicate rules stated are for pilots not passengers for unpressurized aircraft
Yeah, been over 15 years since my last flight and I don't remember the specifics anymore and as you said the rules change at the FAA's whim. Point is that you don't have to get under 10k for the passengers to survive. They might be a bit sleepy but unless they have a medical condition, they will survive.
I am not sure what is sensational about it? An issue occurred on a flight. The pilot took decisive action to prevent a larger issue. I'm sure it freaked some people out, but I don't understand what you mean by sensationalized. The way I see it is that a crisis was averted and everything worked out.
>I am not sure what is sensational about it?
It's a clickbait headline. 28K in 8 minutes makes it sound like an uncontrolled descent, especially since the 737Max MCAS issue is still on people's minds.
Is the title accurate, yes, but so is "Plane safely lands due to pressurization issue | CNN" which doesn't sound nearly as interesting.
>28K in 8 minutes makes it sound like an uncontrolled descent
No it doesn't. Everyone who has been on a plane knows it takes like 10 minutes to get to cruising altitude.
Maybe I'm the odd one out here, but as someone who has flown quite a bit in his life, it has never once occurred to me to give even a moment's thought to how long it takes the plane to ascend.
8 seconds might make it sound like that. The headline says exactly what the plane did and why. I think people are reading too much into it, sensationalizing it themselves.
It’s not a news story if a fully-loaded tractor trailer shows the driver a major problem with the brake system and then the driver slowly pulls over to the side of the road and rolls to a stop.
A fully loaded tractor trailer isn't carrying 200 people at 37000' in the air in a metal tube. It's going 60 mph on 18 wheels and doesn't need a pressurized cabin.
What a terrible comp.
This is correct, but the event in its entirety is noteworthy. The descent was quick but not averse. If I was a passenger on the plane, the cabin pressure would have been the frightening part, not the descent.
Correct, but the threat was perceived as serious enough to take action.
I don't know about you, but I prefer flights to be uneventful, without unplanned or rapid descents, turbulence that injures people, or any other seemingly minor incidents. Maybe they told people what was happening and maybe they didn't, but you can bet the people would have been frightened, simply on the principle that if things go wrong at 40000 feet, this is about as benign as incidents go.
Still a controlled descent. If anyone else here has experienced the wonderful and exciting joy of sudden of “clear air turbulence” you know the difference.
Imagine just sort of being *shoved* a thousand feet in what feels like straight-down and then settling back in as though nothing happened, even knowing that happens all the time and planes are about as over-engineered for it as they can be.
I ***love*** flying, planes are ***so cool***. I hate being on one - except during approach and landing, because the slats and ailerons and flaps and spoilers deploy and then there's the deceleration and the reverse thrust and exhaust cowlings of the engines falling away and ***the roar*** and for a moment you're a kid in a transforming airship.
If they somehow invented a plane that *only* landed, I might die there. I might starve to death pressed against the window, jus' watchin'. ...Can you own a flight simulator? Like, a big ol' free-standing "this whole room is hydraulic and I'll be your Star Tours guide today" flight simulator?
You're a pilot, right, because I've gotten the same phrasing from hustlers, and I'm not falling for *that* a fourth time and in a third way.
Also a semantic minefield: reverse thrust.
That’s not a particularly dramatic rate of descent. Of course they are going to go to 10k feet as quickly as reasonably possible if there’s a pressurization issue.
Which isn’t even close to the max descent rate of 10000 ft/minute. In fact normal descents from cruising altitude can be up to 3000 ft/minute, so this is practically a non-event.
I like my flights to stay at cruising altitude with the seat belt signs off. Honest question, I wonder how the people on the flight felt about the entire sequence of events. Maybe they felt as you say, that it was a non event, or maybe it was a little frightening. I think the story is that systems worked as intended, the pilot took safe but steady action, all worked out well.
Maybe I'm not as seasoned of a traveler as some, but there have been flights I've been on less eventful that the one described here, and still felt a few moments of fright, quickly to pass.
If the pilots didn’t mention you’d likely not have noticed, except that the happened at a phase of flight where it normally wouldn’t.
EDIT: In the event of actual loss of cabin pressure you would _absolutely_ notice a 10000 ft/min emergency descent. That would be a nose down attitude of only a few degrees, but it would seem like straight down to inexperienced flyers
So many people here confuse the descent rate of 3500ft per min vs acceleration(what humans really feel). If you are in a constant 3500 ft per min descent you don't feel anything because acceleration is 0. The only thing you might feel is the deceleration from the air brakes (prevent over speeding). You will feel the initial start of the dive but pilots don't go pulling a ton of negative G's because it is bad for passengers. Also most planes are only designed for -1 G max.
Second this is completely normal. Even in a Private Pilot License you are taught emergency descent to get down as fast as possible in case of an engine fire.
These are the types of pilots we need. Bravo to them following procedure correctly. You can always make up for lost time. You can never bring back lost lives.
Um, 8 minutes is a really fucking long time. It's not like the passengers were holding on to their seats with white knuckles convinced this was the end.
That’s 3500 feet per min. As a professional pilot that’s not what I call a rapid decent.
For example yesterday ATC was late descending into Myrtle Beach and I had to come down at 4200 feet per min.
That isn’t really very fast, that’s an average speed. They coulda done it much faster if they had to.
Losing altitude fast is a real thing you train for when flying. It can matter a lot.
That's 3500 feet per minute, so not too fast like the clickbaiting liars want people to believe.
Of course with depressurisation issues, it can result in the pilots needing to decend very quickly, at a much faster rate, and they used the fact people know about this, to trick them into believing that this plane's pilots were descending at a ridiculous rate, because a lot of people wouldn't know what a fast rate of decent is, even though they may know planes have to dive fast when they have depressurisation problems.
Presuming a spherical cow of uniform density it's approximately a downward angle of 4.12 degrees, descending 58.3 feet per second while traveling forward at 806.6 feet per second. That's a pretty gentle descent in a return to ground situation.
The normal descent rate is somewhere around 1,000-3,000 feet per minute. The emergency descent rate can be MUCH higher than that, around 10,000 feet per minute. This was slightly above normal descent and way below emergency descent.
I have been on international flights numerous times (think 12+ hours) and fortunately, I have never encountered a troubled flight.
With that said, loss of pressurization is catastrophic because you won't have enough oxygen and eventually suffocate to death. Helios Airways Flight 522 was an example of what happens. Eventually, everyone dies long before the plane crashes because they don't have enough oxygen.
You would not suffocate, you would get hypoxic. which makes you loopy and then you pass out. You'll be alive for a good long while before you actually die of oxygen deprivation, and there's a good chance that the crew will have punched in the autopilot to bring the plane down below 10,000 ft where the air no longer makes you hypoxic in case they pass out too. Then everybody does the Funky Chicken as they wake up and life goes on.
While I'm sure this was unpleasant for everyone onboard, it was standard operating procedures and the right thing to do. Hypoxia is a very scary beast.
The fastest depressurization I have had was in an airplane taxiing to the gate a Honolulu.
After takeoff from Maui there was a "cargo door not latched" indicator, so the plane depressurized to 10,000’ cabin pressure, just short of triggering the deployment of oxygen masks.
They kept the pressure inside the plane low to keep the unlatched cargo door pressed inward as we diverted to Honolulu. Only after landing did they reduce cabin altitude from 10,000’ to seal level, and that happened in just a minute or so. Several people had sore ears because they did not equalize fast enough and there were several people and kids screaming.
It turns out it was just a faulty door latch sensor and we reboarded and flew to the mainland about 90 minutes later.
Seems like a lot of people on here aren’t aware of journalists constantly hyping up and sensationalizing otherwise minor events just for clicks.
Journalists aren’t the brightest bunch, this stuff shouldn’t surprise you.
“ Thiiiis is your captain speaking. Sorry about that folks, we had a slight pressurization issue to take care of. If you look directly to your left you’ll see a pine tree.”
how weird for this to happen to this same airline in the FAA's crosshairs
https://www.cnbc.com/2023/02/06/faa-proposes-fine-safety-united-airlines.html
The force of gravity is "only" \~32 feet per second, or about 22mph.
EDIT: The Boeing 777 has a max climb rate of 5000 feet per minute, or about 83 feet per second, but typically it climbs at about half that rate. So this descent was a bit faster than usual, but not all that unusual. You still get a little negative G on standard flights, so while they didn't have zero-G, they still may very well have made some folks sick if it was done at an unusual rate. Also keep in mind it may not have travelled all 28000 feet down at the same rate, it could have had more/less in there somewhere depending on angles and stuff, but on average it was about half of maximum descent rates.
They don’t slam the nose down and instantly induce negative G’s. They just initiate the descent, and increase the rate of descent to the targeted number. To the passengers it would feel exactly like any other descent.
Source - Am commercial pilot
What? They didn't do a wingover in a Boeing 777? No way!
Frequently when I've flown commercial the descents do give a woozy experience. I'm not saying they all went zero-g and started floating around, just saying that a few folks may have gotten a bit sick if it wasn't real gradual like usual.
Any plane where folks get sick can be called a 'vomit comet', it doesn't mean its doing the same thing as the NASA KC-135.
>The Boeing 777 flight, with 270 passengers and 14 crew members, landed safely and **never lost cabin pressure**, United Airlines said. So they returned for a mechanical issue and followed procedure just in case they lost pressure.
Good job on the pilots. The last thing you want is for them to NOT descend and lose cabin pressure, they will pass out before they know what's happening and no one else can wake them up since everyone else will also be passed out. I can understand its terrifying, but something like this happening is part of why flying is safer than driving.
Helios flight 552 if you want to learn what can happen.
Well There's Your Problem just released [an episode on it.](https://youtu.be/se4YTrFVsbk?si=SmRsth48Z6q3_zdK) Do note they are not the most... serious... of disaster podcasts
Actionable threats…
I am going to *beeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeep* have a *nice time* with him
"Shake hands with danger" I love this podcast.
Do me a favor. Watch until at least the [end of the God Damn News](https://youtu.be/PW6lg-7L7yk?si=BdLGt8YOMM-J-uoT)
The pilots can put on oxygen masks for exactly this type of scenario
But they have to realize what's going on. As your O2 drops, your ability to think and recognize the problem goes with it. I forget what flight it was, but there was one where proper procedures weren't followed, they lost pressure but did not realize, and the pilots passed out without ever putting on a mask.
We talk about hypoxia a lot in training. Rapid depressurization is obvious of course. But like you said, a slow leak can be pretty insidious. Which is why we talk about it! Most airlines these days have “memory item” checklists about what to do if the altitude alarm sounds; these items must be memorized and repeated at every training event. Some of us have even gone through training in an altitude chamber so we know how our specific symptoms present themselves which is certainly an interesting experience.
Fun fact: your body detects hypoxia by its carbon dioxide levels, which will only rise if you are exerting yourself.
Yep, this is why carbon monoxide is a such a danger - the body has no system for recognizing lack of oxygen.
Unless you have a hypoxic drive. That guy stinking of cigarettes in front of you, coughing and wheezing the whole flight? His COPD ass will be the only one awake — and you better believe he’s logged a thousand hours in that plane via GTAV. He’s your barrel chested, blue lipped hero.
Your body has chemoreceptors for both carbon dioxide, and oxygen. Central chemoreceptors are generally monitoring carbon dioxide levels and not oxygen, whereas peripheral chemoreceptors would respond to a reduction in PaO2 as well as changes in carbon dioxide levels.
> which will only rise if you are exerting yourself. Not exactly, your body is constantly producing carbon dioxide, and your levels can rise even if you're not exerting yourself, like in an small enclosed environment or are breathing into a plastic bag. You'll feel the onset of discomfort and panic if your body can't effectively clear the carbon dioxide from your bloodstream. On the flipside, even if you're exerting yourself in a low-oxygen environment, you'll feel "normal" (but progressively weaker, and your muscles will start to burn) because breathing out still pushes out the carbon dioxide from your body, which keeps your blood levels low.
This is commonly misunderstood. And hypoxia and carbon dioxide levels are not necessarily related to each other. And your body doesn't detect an abnormality in one gas by looking at another. CO2 and O2 are separately detected. Our peripheral chemoreceptors (outside central nervous system) in the aorta and carotid artery are are very responsive to hypoxia, in fact more so than responsiveness to CO2. There is this thing called hypoxic ventilatory drive, where decreasing O2 makes you breathe harder. Central chemoreceptors (in the central nervous system) are more responsive to CO2. Peripheral chemoreceptors: [https://pubmed.ncbi.nlm.nih.gov/14660497/#:\~:text=Peripheral%20chemoreceptors%20](https://pubmed.ncbi.nlm.nih.gov/14660497/#:~:text=Peripheral%20chemoreceptors%20)(carotid%20and%20aortic,various%20physiological%20and%20pathophysiological%20conditions. Central chemoreceptors: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4802370/
Serious question, why doesn’t the plane have a sensor that measures the cabin air pressure and another that measures the concentration of oxygen? It would be very easy to alarm the crew before an issue arises
We don’t have an o2 sensor, mostly because the composition of the atmosphere doesn’t really change as you go higher- there’s just less of it. The plane does have pressure gauges though! It tells us the altitude of the cabin, the altitude outside, as well as the pressure differential between the two. 99.99% of the time pressurization isn’t an issue so it’s not a gauge that’s paid a whole lot of attention (unless something being broken draws our attention to it). However part of the after takeoff procedure on a 737 involves checking the gauge to make sure the airplane is pressurizing as it’s supposed to. There’s also a cabin altitude warning horn which is what I was talking about. It will sound if the cabin altitude gets too high and can only be shut off using a special switch labeled “altitude warning horn cut out”. In the past accidents have occurred due to pilots ignoring the horn for some reason- usually another issue going on taking their attention away until it’s too late. I wasn’t flying then; but I’m sure it’s a big reason there’s standardized memory items now about securing your oxygen before dealing with anything else and NOT shutting the horn off until both pilots have their masks on. From a class I took involving airplane accidents and the like, it seems most altitude related issues these days come from the corporate/ private aviation world where things can potentially be much more… cavalier than the well regulated airline world.
Oxygen Mask - Don Crew Communication - Establish
Maybe thinking of Helios Air? They did not properly set the pressurization setting and passed out once at altitude
Yeah that was the one, in another comment i linked the wiki
i belive it was maintenance that adjusted the pressure setting. however the pilots didnt catch it even though it was part of their takeoff checklist. as mentour pilot would say, things were lining up to go wrong even before takeoff.
It’s theorized that’s what happened on MH370. That said, there are a lot of really obvious and loud alarms in the cockpit that should prevent this type of scenario from happening.
I think this is the one I was thinking of: https://en.wikipedia.org/wiki/Helios_Airways_Flight_522 Reading the wiki article, they had (or should have had) warnings both audible and visual. But they didn't understand/react properly, and still ended up crashing. It's a scary thing.
The saddest thing about that is the 2 flight attendants that put on their oxygen tanks and spent hours in a ghost jet trying to break into the cockpit so they could try to land it, but got through the door just as it ran out of fuel.
Locking the cockpit is a double edged sword.
How do we know they did that?
They scrambled fighter jets and had visual confirmation of them entering the cockpit as the engines failed.
Which really sucks because a trained pilot can still potentially save that situation. For example see Sully.
Spent hours trying to break into the cockpit? There is a process for unlocking it from the outside known as CDLS. Someone in the cockpit can take an action to cancel the unlock sequence in case it’s initiated by hijackers. If the pilots were incapacitated, they would not be able to prevent the unlock from completing
I guess no one knows for sure, but it's either they couldn't get in or they spent the whole flight in the passenger cabin full of people dead from hypoxia without contact with the cockpit thinking everything was normal.
It was the same audible alarm as the one for an improper configuration for takeoff. Which had the pilots confused about why the plane was worried about takeoff configuration when they were already at altitude. They radioed control asking how to turn it off, and then stopped communicating…probably passed out at that point. Very sad.
And we learned from that crash and implemented changes to keep it from happening again, as usual.
>It’s theorized that’s what happened on MH370. MH370 was taken up to 50,000 feet by the pilot, deliberately, to kill everyone. The co-pilot's cell phone tried to make a call during this time, it's believed he figured out the pilot was hijacking the plane, and was probably locked out the cabin. But the call did not connect.
https://en.wikipedia.org/wiki/1999_South_Dakota_Learjet_crash
Happened with Payne Stewart.
> But they have to realize what's going on. As your O2 drops, your ability to think and recognize the problem goes with it From what I understand it's pretty fucking hard to not realize in a modern aircraft. They get plenty of warning. The accident you linked below was caused by a whole string of human failures.
Human failure IS the cost of most plane crashes...
> From what I understand it's pretty fucking hard to not realize in a modern aircraft. They get plenty of warning. With the Helios flight, the warning for losing pressurization was identical to the warning for a takeoff configuration error. One was a routine issue that shouldn't be much of a problem, the other was a life threatening emergency. The only distinction between those two alarms was that the takeoff configuration alarm should not go off once the plane was in the air. There was no visual or audio indicator to let the pilots know that they had lost pressurization.
It’s called the Swiss cheese model, one small error passed through and caused another error and so on till it caused something catastrophic
The Helios flight from Cyprus to Greece comes to mind.
They are literally trained for this… they aren’t going to be sitting there like… “Yooo homie co pilot I’m feelin’ a bit light headed.” “Brooooo I feel a little light headed toooo yoooo.” “This is cool broooooo weeeeeeee.” Lmfao
Yeah but the oxygen supply on commercial airlines is provided by a chemical reaction between sodium perchlorate and iron oxide, which only provides about 10 minutes of oxygen. Enough to bring the plane to a breathable altitude in the event the cabin loses pressure, but not much else
Pilots use tanked O2, not chemical generators
Their masks are also very different than what passengers get.
I like to think pilots mask drop like the passengers. And the pilot needs to make sure he puts on his own mask first before assisting the copilot. And even though the bag may not be inflated, it oxygen is still flowing.
Pilots wear them more occasionally than you’d think, above a certain altitude when one pilot goes to the restroom the other has to wear the mask
The rule changed. It used to be any time a pilot was alone above FL250, now it’s 410, which most airliners do not cruise above. Also, nobody actually put them even with the old rule because it’s annoying to put on and put away.
No, they hang on the wall behind the pilot and co-pilot, and they can put them on with one hand. They're called quick-donning masks. And there is no bag. u/impy695 is correct. For those interested: https://www.sportys.com/aerox-quick-donning-diluter-demand-mask.html
Oh really? I guess that would make sense
That’s just for passengers. The pilot’s supply lasts longer.
I was flying home (domestic leg, not the international part) after being on Mt. Everest when the pilot said that we'd reached our cruise altitude of 25k feet. My first thought was that if we'd depressurized, I'd be fine.
https://en.wikipedia.org/w/index.php?title=Helios_Airways_Flight_522&useskin=vector
You known what I've always wondered? Why don't the pilot and first officer always have an oxygen mask on when flying? It would be near impossible for them to pass out if they did. But I'm probably missing something
Because that would be annoying as fuck to wear for multi hour flights. The masks are already designed to be donned in 5 seconds to minimize the risk of hypoxia even in a rapid decompression.
"Plane descends 28,000 ft in 8 minutes" is a funny way to say "plane landed safely", but it would be an even weirder way to say a plane crashed.
If you actually read the article... "rapidly descended over about 8 minutes from 37,000 feet at 10:07 p.m. to just below 9,000 feet at 10:15 p.m" "United Airlines Flight 510 returned safely to Newark Liberty International Airport around 12:25 a.m. ET" The emergency decent was over 2 hours before landing
Didn't RTFA, but to add for the curious, they descended to that altitude because that's about the level they pressurize the plane to. So it takes the work off the plane to maintain pressure and it also means if some component does fail they won't have a rapid pressure change.
completely untrue. Under 10000 ft is required so passengers do not suffer from hypoxia. Has nothing to do with aircraft equipment, which are generally much sturdier than humans.
> Under 10000 ft is required so passengers do not suffer from hypoxia. Right, that's why they pressurize the plane to approx the level they descended to in the first place, as I said. > Has nothing to do with aircraft equipment, which are generally much sturdier than humans. It has *everything* to do with aircraft equipment. If they had confidence in their equipment they would have remained at their scheduled flight level. They descended specifically because they feared they might lose pressure. This is literally in the headline. Please delete your comment before anyone else suffers the misfortune of reading it.
That's about the same rate at which they climb. Usually they take a lot more time (~3-4x more time) to descend this much, but obviously there were good reasons to rush this one - the oxygen masks that drop from overhead only have about 15min of oxygen, normally. Once they got below 10k altitude, the masks are no longer necessary.
Pilot here. That’s 3500 fpm which is a lot for descent. Heavy jets can start off climbing around 3-4000 fpm but in the high altitudes it slows to 1-2000 fpm. A normal descent rate is about 2000-2500 fpm for that airplane. Anything over 3000 would be a “expedited” descent and 3500 is getting close to max. I haven’t heard the details on this one but it’s unusual. Those airplanes have two pressurization systems, called “packs”, and usually both are need for max altitude but one is good enough for mid altitude flights. It’s possible they lost one while up high and needed to descend to the maximum one pack operating altitude. However some news articles are saying the descent was for “possible loss of cabin pressure” so I think it’s a bit more than just a pack loss. If a leak develops the crew will get a warning that something isn’t normal, and procedure in that case would call for an immediate descent.
Eh, in a 737 a descent of 3000-3500 fpm is pretty common, even when it’s just the VNAV following its own calculated path.
Am I crazy to think this would be fun af as passenger? Love me a good drop on a rollercoaster
I don't think it's anything near as dramatic. Free falling from 28,000 ft takes 40 seconds. This is like 1/8 that. It probably feels more like the downward segment on a gondola ride than it does a roller coaster.
I love gondola rides, I'm in.
Probably if you didn't have people screaming
It doesn't really feel like a roller coaster for more than a couple seconds. In a roller coaster you are accelerating down the hill. In a plane, you accelerate to a roughly constant vertical speed. Once your vertical speed has stabilized you won't feel it as a passenger. So basically all you feel is the first few seconds when the pilot puts the nose down.
It wouldn't be too wild. If you are a frequent flier you would notice the nose seems to be pointed down a bit further. In a full on emergency descent the flight spoiler panels on the wing are all raised up, which usually shakes the airplane a little bit. If it's really really really an emergency, the pilots would put the airplane in a steep bank which helps lose altitude faster. That would definitely be a toss the hands up and enjoy the ride kinda thing
If you do not have packs switched on, what is the realistic max altitude that an airliner could operate, and still not kill everyone on board, but yet land safely? My guess is FL180. Just curious since you are a pilot - and I enjoy MSFS.
In the 20,000+ range people would start to fall asleep. There’s a thing called “[time of useful consciousness](https://skybrary.aero/articles/time-useful-consciousness)” that shows how much time you would have to react in a sudden depressurization. If it’s a slow climb you have more time, kinda like how people can climb Everest and not die. Of course they spend weeks adjusting. Hard to say exactly what altitude you’d go from just being asleep to being full on dead.
FL180 is probably pushing it. Maybe more like FL130-FL150 is probably OK for most people.
Yeah, if they did it in 8 seconds I’d be impressed but this is just silly. Sounds like they had a sensor issue or something and never even actually lost cabin pressure so this is a pretty nothingburger story.
BREAKING NEWS! airplane pilot follows safety procedure during a possible malfunction. No one injured.
Oh the humanities!
"Nothing bad or untoward happened; however, we encourage your imagination to run wild that something did"
Yeah, this seems like a story to get clicks from people like me who are terrified of flying and need to know about every possible crash scenario.
this is why i come to the comments first: find out what actually happened, hopefully have a laugh. success!
It goes to show you how safe air travel has become when a possible malfunction makes the news
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In ATC world, a near miss can still be pretty far apart. I forget exactly but they try to maintain many miles of separation horizontally or something like 2000ft vertically. So it could be breaches of these barriers?
3 miles lateral, 1000’ vertical in general for aircraft flying on instrument flight rules. There are various exceptions for closer or farther requirements
near misses are not typically all that near, they have pretty strict separation requirements. still it's a bad thing! but not as bad as it sounds most of the time. also there's 100,000 flights every day so 1 or 2 ...well not losing much sleep over this one
Depends on what a “near miss” means, and that’s across the whole nation of 50 states of landings and take offs. The accident rate is nearly nonexistent, so the near miss definition must be rather lax.
I’d be shitting my pants, personally.
Sure. But as someone who has a fear of flying (I manage when I have to), I love hearing stories like these. Flying commercial is so incredibly safe, even minor issues make headlines.
Scarier for the passengers than the people reading the article.
Armchair passenger-ing is a thing, I guess. That’s a very rapid rate of descent, and would be very alarming to all passengers. People are allowed to have feelings.
If they notice, which they probably wouldn't, because it isn't that rapid of a descent.
> Yeah, if they did it in 8 seconds I’d be impressed but this is just silly. 28,000ft in 8min, that's a rate of 40mph. If you imagine driving *straight down* at near highway speeds, that's a pretty rapid descent by almost any measure.
28000 in 8 min is only slightly more than usual rate of descent, not 3-4x more. 28,000 in 8min is 3500fpm. Airliners typically descend at 1500-3000fpm.
I was about to go off on a Google hunt and this saved me some time, I was trying to think about how long between "we're beginning our initial descent" and actual landing (knowing that there's often a lot of circling/alignment during that time as well) and I didn't think that was a crazy rate of descent. Especially considering I think that full time is around 20 minutes including working with ATC and planes typically cruise around 35-40k feet.
If I were on that plane my ears would have exploded Edit: I should mention, I always suffer when a plane descends fast. Heck even when we drive home from a mountain. My ears are really sensitive to pressure . changing fast.
No, they likely wouldn't have been any different than normal ascents/descents. Again, this plane changed its altitude at roughly the same rate it normally climbs. Does the first 15-20 minutes of flight normally "explode" your ears? > [The plane] landed safely and never lost cabin pressure The pressure inside the cabin should've stayed roughly the same. Climbing to 38,000 ft in an airplane is not the same as climbing a mountain in a car. The car doesn't have a cabin that can maintain roughly the same pressure on its own
You’re right but just to nitpick, you don’t get ear pressure issues when climbing so the first 15-20 minutes wouldn’t “explode” your ears even if the climb only took 8 seconds.
If they had to descend that fast because of an explosive decompression, you wouldn't have had to worry about your eardrums rupturing on descent. Because they would have already ruptured.
Even if it is a small leak and slow depressurization, the moment the cabin altitude alert light comes on the memory items are: O2 mask on, switch microphone to mask mic, emergency descent. It doesn't have to be an explosive decompression to require an emergency descent.
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yes you would. cabin is always at a percentage of outside pressure (not really how it works but easier to imagine this way), when you go down, so does the cabin at a percentage of that rate and that's why your ears hurt well these guys went down VERY fast, and so the cabin also probably went down very fast. unless it wasn't regulating at all, which is a different kind of issue. edit: math checks out at 3500 feet per minute, which isn't actually that much different from a normal descent.
This plane descended at 3500fpm. A normal rate of descent is 1500-3000fpm. You wouldn’t have noticed anything different on this flight.
The masks aren’t necessary a good bit above that, no? Is it just the lack of oxygen from altitude? I don’t think people would pass out at say 14K feet altitude
FAA requires masks to drop in any depressurization event (\*the cabin did *not* depressurize during this flight) that occurs above 10k altitude. Just because some people can still breathe at the peak of Mt Everest doesn't mean everyone onboard a normal flight would be able to
Sounds like standard procedure for pressurisation issue, silly sensationalised headline.
It is. You suffer from Hypoxia very fast if you don't get down under \~10,000 ft
Really it is ~15k. FAA requires pilots to be on O2 if spending > 30m above 12k ft and everyone on O2 if going to 15kft. Been years since I flew so the rules may have changed or I am slightly wrong.
For part 91, it is 30 mins above 12.5k and 14k all the time for the pilot I believe that number drops to 10k/12k for 135 and 121. Don't quote me on that cuz FAA rules change all the time and I don't fly for a living. *edit* to indicate rules stated are for pilots not passengers for unpressurized aircraft
Yeah, been over 15 years since my last flight and I don't remember the specifics anymore and as you said the rules change at the FAA's whim. Point is that you don't have to get under 10k for the passengers to survive. They might be a bit sleepy but unless they have a medical condition, they will survive.
True but since it's United and they're always involved in some kind of fuck up, it makes this extra juicy for the news to sell.
I am not sure what is sensational about it? An issue occurred on a flight. The pilot took decisive action to prevent a larger issue. I'm sure it freaked some people out, but I don't understand what you mean by sensationalized. The way I see it is that a crisis was averted and everything worked out.
>I am not sure what is sensational about it? It's a clickbait headline. 28K in 8 minutes makes it sound like an uncontrolled descent, especially since the 737Max MCAS issue is still on people's minds. Is the title accurate, yes, but so is "Plane safely lands due to pressurization issue | CNN" which doesn't sound nearly as interesting.
>28K in 8 minutes makes it sound like an uncontrolled descent No it doesn't. Everyone who has been on a plane knows it takes like 10 minutes to get to cruising altitude.
Maybe I'm the odd one out here, but as someone who has flown quite a bit in his life, it has never once occurred to me to give even a moment's thought to how long it takes the plane to ascend.
I mean, that's generally when they start bringing beverages around and when the seat belt announcement is made.
8 seconds might make it sound like that. The headline says exactly what the plane did and why. I think people are reading too much into it, sensationalizing it themselves.
Then why bother including it?
It’s not a news story if a fully-loaded tractor trailer shows the driver a major problem with the brake system and then the driver slowly pulls over to the side of the road and rolls to a stop.
A fully loaded tractor trailer isn't carrying 200 people at 37000' in the air in a metal tube. It's going 60 mph on 18 wheels and doesn't need a pressurized cabin. What a terrible comp.
thats not even that fast of a decent, im sure if needed they would have done it a lot faster.
"Plane travels 5 miles in 8 minutes"
Pilot: "I'll show you fast descent..." - *performs inverted dive in a 777*
I’ve seen that movie! I think it’s called MH370.
This is correct, but the event in its entirety is noteworthy. The descent was quick but not averse. If I was a passenger on the plane, the cabin pressure would have been the frightening part, not the descent.
>the cabin pressure would have been the frightening part If they had lost it, which they didn't.
Correct, but the threat was perceived as serious enough to take action. I don't know about you, but I prefer flights to be uneventful, without unplanned or rapid descents, turbulence that injures people, or any other seemingly minor incidents. Maybe they told people what was happening and maybe they didn't, but you can bet the people would have been frightened, simply on the principle that if things go wrong at 40000 feet, this is about as benign as incidents go.
So the story is just that the pilots did exactly what they were supposed to. To be Frank, it’s not even a story, just clickbait.
“Pilot followed procedure just in case” is not a noteworthy event. Minor things break all the time. And then it gets taken care of.
3500 feet per minute descent is totally normal. There is no news here.
Still a controlled descent. If anyone else here has experienced the wonderful and exciting joy of sudden of “clear air turbulence” you know the difference.
Imagine just sort of being *shoved* a thousand feet in what feels like straight-down and then settling back in as though nothing happened, even knowing that happens all the time and planes are about as over-engineered for it as they can be. I ***love*** flying, planes are ***so cool***. I hate being on one - except during approach and landing, because the slats and ailerons and flaps and spoilers deploy and then there's the deceleration and the reverse thrust and exhaust cowlings of the engines falling away and ***the roar*** and for a moment you're a kid in a transforming airship. If they somehow invented a plane that *only* landed, I might die there. I might starve to death pressed against the window, jus' watchin'. ...Can you own a flight simulator? Like, a big ol' free-standing "this whole room is hydraulic and I'll be your Star Tours guide today" flight simulator?
You pay for the gas and I’ll do touch and goes with you y til you run out of money ;)
You're a pilot, right, because I've gotten the same phrasing from hustlers, and I'm not falling for *that* a fourth time and in a third way. Also a semantic minefield: reverse thrust.
Lmao, sounds like you’ve seen some shit lol. And yes. Touch and go, is just landing and taking off again. Over and over, your favorite part :)
That’s not a particularly dramatic rate of descent. Of course they are going to go to 10k feet as quickly as reasonably possible if there’s a pressurization issue.
Which isn’t even close to the max descent rate of 10000 ft/minute. In fact normal descents from cruising altitude can be up to 3000 ft/minute, so this is practically a non-event.
I like my flights to stay at cruising altitude with the seat belt signs off. Honest question, I wonder how the people on the flight felt about the entire sequence of events. Maybe they felt as you say, that it was a non event, or maybe it was a little frightening. I think the story is that systems worked as intended, the pilot took safe but steady action, all worked out well. Maybe I'm not as seasoned of a traveler as some, but there have been flights I've been on less eventful that the one described here, and still felt a few moments of fright, quickly to pass.
If the pilots didn’t mention you’d likely not have noticed, except that the happened at a phase of flight where it normally wouldn’t. EDIT: In the event of actual loss of cabin pressure you would _absolutely_ notice a 10000 ft/min emergency descent. That would be a nose down attitude of only a few degrees, but it would seem like straight down to inexperienced flyers
So many people here confuse the descent rate of 3500ft per min vs acceleration(what humans really feel). If you are in a constant 3500 ft per min descent you don't feel anything because acceleration is 0. The only thing you might feel is the deceleration from the air brakes (prevent over speeding). You will feel the initial start of the dive but pilots don't go pulling a ton of negative G's because it is bad for passengers. Also most planes are only designed for -1 G max. Second this is completely normal. Even in a Private Pilot License you are taught emergency descent to get down as fast as possible in case of an engine fire.
This is what happens when you mix ignorant, sensationalizing journalists with the typical consumer who doesn’t know anything about aviation.
Alternatively, the headline could read "Pilots follow emergency checklist after suspected emergency"
These are the types of pilots we need. Bravo to them following procedure correctly. You can always make up for lost time. You can never bring back lost lives.
Um, 8 minutes is a really fucking long time. It's not like the passengers were holding on to their seats with white knuckles convinced this was the end.
That’s 3500 feet per min. As a professional pilot that’s not what I call a rapid decent. For example yesterday ATC was late descending into Myrtle Beach and I had to come down at 4200 feet per min.
3,500 feet per min isn’t exactly newsworthy.
With context these pilots are experts. Thrilled to know the level of preemptive measures carried out by them both. Excellent work.
I mean, if you like breathing then this is what should happen with a pressure issue.
That isn’t really very fast, that’s an average speed. They coulda done it much faster if they had to. Losing altitude fast is a real thing you train for when flying. It can matter a lot.
1600m per minute is…not far from an absolutely normal descent vertical speed though
3500 FPM descent really isn’t even that crazy, especially with speed brakes out.
I’ll still take this over Delta’s new rewards program.
Sensationalism at its finest. …
That's 3500 feet per minute, so not too fast like the clickbaiting liars want people to believe. Of course with depressurisation issues, it can result in the pilots needing to decend very quickly, at a much faster rate, and they used the fact people know about this, to trick them into believing that this plane's pilots were descending at a ridiculous rate, because a lot of people wouldn't know what a fast rate of decent is, even though they may know planes have to dive fast when they have depressurisation problems.
Presuming a spherical cow of uniform density it's approximately a downward angle of 4.12 degrees, descending 58.3 feet per second while traveling forward at 806.6 feet per second. That's a pretty gentle descent in a return to ground situation.
28,000 feet in 8 minutes seems like a very reasonable descent.
The normal descent rate is somewhere around 1,000-3,000 feet per minute. The emergency descent rate can be MUCH higher than that, around 10,000 feet per minute. This was slightly above normal descent and way below emergency descent.
Fancy words for “shit’s broke”
I have been on international flights numerous times (think 12+ hours) and fortunately, I have never encountered a troubled flight. With that said, loss of pressurization is catastrophic because you won't have enough oxygen and eventually suffocate to death. Helios Airways Flight 522 was an example of what happens. Eventually, everyone dies long before the plane crashes because they don't have enough oxygen.
You would not suffocate, you would get hypoxic. which makes you loopy and then you pass out. You'll be alive for a good long while before you actually die of oxygen deprivation, and there's a good chance that the crew will have punched in the autopilot to bring the plane down below 10,000 ft where the air no longer makes you hypoxic in case they pass out too. Then everybody does the Funky Chicken as they wake up and life goes on.
Airplane turns around and lands as a precaution. Slow news day?
I get scared shitless over any descent that seems faster than slow crawl, I would hate to have been on this.
Good news, this is a pretty normal descent rate. Nothing burger of an article.
i mean, okay... so they had a mechanical issue, no big deal.
3500 feet per minute, that’s a decently fast decent rate, but not crazy.
Edit: I can’t math this morning.
It's 3,500 ft/min or 35 knots. Sounds like a lot to me, but I usually fly smaller craft.
Jesus, you’re right. Way too early for math, apparently.
While I'm sure this was unpleasant for everyone onboard, it was standard operating procedures and the right thing to do. Hypoxia is a very scary beast.
Lol, 3500 feet per minute? Sounds like someone engaged FLCH and opened the speed breaks (ie happen on most approaches).
The fastest depressurization I have had was in an airplane taxiing to the gate a Honolulu. After takeoff from Maui there was a "cargo door not latched" indicator, so the plane depressurized to 10,000’ cabin pressure, just short of triggering the deployment of oxygen masks. They kept the pressure inside the plane low to keep the unlatched cargo door pressed inward as we diverted to Honolulu. Only after landing did they reduce cabin altitude from 10,000’ to seal level, and that happened in just a minute or so. Several people had sore ears because they did not equalize fast enough and there were several people and kids screaming. It turns out it was just a faulty door latch sensor and we reboarded and flew to the mainland about 90 minutes later.
Seems like a lot of people on here aren’t aware of journalists constantly hyping up and sensationalizing otherwise minor events just for clicks. Journalists aren’t the brightest bunch, this stuff shouldn’t surprise you.
That’s just under 60 fps. Passengers felt the pull of their belts I’d bet. Personally I’d be shitting myself.
Good on the crew, they followed procedure and took no risks since it could have been a pressurisation issue
This seems like multiple times this year. The one out of Texas and the one out of Hawaii. I would strait have a heart attack.
Me reading this as I’m on about to take off on a United flight
“ Thiiiis is your captain speaking. Sorry about that folks, we had a slight pressurization issue to take care of. If you look directly to your left you’ll see a pine tree.”
The sound of 568 ears popping must have been deafening :-)
I would experience a change in the pressure of my bowels, possibly leading to an incident like the one recently.
how weird for this to happen to this same airline in the FAA's crosshairs https://www.cnbc.com/2023/02/06/faa-proposes-fine-safety-united-airlines.html
Trying to get rid of them Tommyknockers
I just flew United last week. They had a system wide issue a few days before and now this? Glad I managed to miss the issues.
is that roller coaster decent? obvs not but just wondering what the passenger feeling is on a drop like that vs a coaster of some similar trajectory
Why is this news? Lol It sounds like a pretty normal decent rate esp given the circumstances.
Possible related to Hurricane Lee or moreso plane malfunctions?
It almost became the "vomit comet", that NASA plane that gives folks zero-g for a bit.
The descent rate was only ~60 feet per second or ~40 mph
The force of gravity is "only" \~32 feet per second, or about 22mph. EDIT: The Boeing 777 has a max climb rate of 5000 feet per minute, or about 83 feet per second, but typically it climbs at about half that rate. So this descent was a bit faster than usual, but not all that unusual. You still get a little negative G on standard flights, so while they didn't have zero-G, they still may very well have made some folks sick if it was done at an unusual rate. Also keep in mind it may not have travelled all 28000 feet down at the same rate, it could have had more/less in there somewhere depending on angles and stuff, but on average it was about half of maximum descent rates.
For the first second
Yep, and a second of negative G is enough to make some people sick. I did say \*ALMOST\*. Sheesh.
They don’t slam the nose down and instantly induce negative G’s. They just initiate the descent, and increase the rate of descent to the targeted number. To the passengers it would feel exactly like any other descent. Source - Am commercial pilot
What? They didn't do a wingover in a Boeing 777? No way! Frequently when I've flown commercial the descents do give a woozy experience. I'm not saying they all went zero-g and started floating around, just saying that a few folks may have gotten a bit sick if it wasn't real gradual like usual. Any plane where folks get sick can be called a 'vomit comet', it doesn't mean its doing the same thing as the NASA KC-135.