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Airline Pilot Technical Theory, Human Factors, Aircraft Accidents Adam Howey Airline Pilot Technical Theory, Human Factors, Aircraft Accidents Adam Howey

Oxygen

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Transcript Start

00:04

Adam Sam oxygen important. Yeah, oxygen. Very important to us in. An aeroplane, why is it important to us? Well, because we take the most precious cargo known to, man, take it up into the stratosphere and although there's a lot of risks associated with flying at 500 miles an hour in the stratsphere one of the biggest hazards to us is the environment itself.

00:31

So 35,000 feet. Well, the passengers are innocently sipping, their gin and tonic actually outside. It's minus 56 degrees. And the partial pressure of oxygen is extremely low. Yeah, so, I mean, what's your favourite attitude? Yes, 35 37. Maybe. Yeah. This is a point to be made there, which is it?

00:56

We could be between. Yeah, 34 and 40. Let's say, yeah, there's a big big difference between your time of useful consciousness. Like effects of a decompression. Just between a few thousand feet there. Yeah. It's almost like exponential, isn't it when you get up to those higher? Yeah. Because shoots are they, the partial pressure and the pressure is, it's reasonably linear.

01:18

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Physiology

As you go up, it's haemoglobin that is has the exponential change. So the haemoglobin the red blood cells that carry the oxygen around the body. They're 98% saturated at sea level. When you get to 10,000 feet, they're still 90% saturated. But by the time you get to 20,000 feet, they're only 60% saturated, right?

01:40

Just like an exponential decrease in the ability of the body to get the oxygen into the haemoglobin and anything you can really compare it. To being up with those, altitudes would be like climbing Mount, Everest people, you know, not everything's about 30,000 feet high and we never been saying everyone that goes to the top level is to generally use oxygen and because you just couldn't survive.

02:02

Yeah, he told me some people. Climb it without auction. Well, yeah, I think they do, but I think that takes them a long time because I think they do it and their climate is and they take things very slowly getting up to the top and base camp is like 20,000 feet or something.

02:17

So they have to acclimatise there, you climb there and then it's quite a slow climb, but I guess they're not. Then trying to fly an aeroplane at the top three or climb around, just doing kind of hopefully, simple ish tasks. Yeah. So space, you're saying they've got but they've got physical, they need the oxygen for physical activity, whereas we would like to say, we use it in our brain, our brain.

02:38

Yeah, the brain is like, really hungry organ. So, use a lot of oxygen. I say that's interesting because if anybody ever had the chance to experience the effects of hypoxia safely and, you know, volunteer to do so it's kind of would be really useful for your career so I mean how high is Kilimanjaro.

02:57

I think its about 20,000 and you can like kindly gently walk up. I think people can get up to something like that oxygen and stuff. Yeah, I mean you could hire a hyperbaric chamber or something because there's a list of common symptoms of hypoxia. But what is unique to you is that the order that they occur in.

03:17

So they occur in a different order to every for every individual, but they will always occur in that order to you. So, you know, there could be some use in getting hypoxia course. And then recognising what your first? Yeah, but yeah, they're physiology of of oxygen, obviously, without oxygen.

03:33

Eventually we die and hypoxia is lack of oxygen. There's different types of hypoxia. You know, there's toxic hypoxia which you can get from drinking alcohol for examp course, the gin and tonic I was talking about earlier, the passengers are already slightly ever. So slightly hypoxic. Yep, at the cabin altitude that we're operating at with an alcohol will affect the haemoglobin's.

03:56

Ability to saturation of oxygens, take up oxygen smokers carbon monoxide, the red blood cells prefer carbon monoxide. So they inhibit the take-up of oxygen you know and if you've got a faulty boiler in your house you know that could be like fatal to people if they're if it's got a serious carbon monoxide leak.

04:16

So that's called toxic hypoxia. But I think what we talk about today is hypoxic hypoxia which is just the lack of the oxygen or the pressure of the oxygen in the air around. You Interestingly, I remembered like when we were flying light aircraft. There was always a carbon monoxide detector on.

04:34

Yeah. In front of you on the firewall. And then I suddenly thought, why don't we have that, you know, aircraft but obviously we're not bleeding. We're not sat right next to the piston engine bleeding, the heat air like in a car. So heat exchanger situation. So maybe but then we don't have any kind of like toxicity.

04:50

You would think a multi-million pound aircraft. You think like one of those tiny little carbon monoxide sensors that cost probably like a pound? Maybe we could take one in? Yeah. Maybe I'll just take one in my flight bag So, yeah. So, okay. So we're kind of touched there on you mentioned cabin altitude so okay, so aeroplanes flying through the stratosphere, 36, 37,000 feet, there's not enough oxygen there for us.

05:15

If we were outside the aeroplane, right? So, our aircraft are pressurised to a, what we call a cabin altitude. So what, what is a, how does that work? What does what? What's a cabin altitude? Yes, it's not sea level pressure inside one, why not? Because I think it's a compromise between the safe enjoyable altitude of 8,000 feet typically and then how strong you need your aircraft structure to be.

05:45

Yeah. So there's a differential pressure between the pressure on the outside of the aircraft, the altitude that you're flying at and the cabin altitude is on the inside. And so there's a structural limit which is usually about eight or nine PSI and we have an instrument in the flight deck that just is, is what their differential pressure is right now.

06:05

And so the aircraft designed to that structural limit And so that means that the air inside the cabin is 8,000 feet. It's like you're at the top of an 8,000 foot mountain Although the aircraft is physically in the crews at 35,000 feet but there's a point where you've got a, you've got to go from sea level to 8,000 feet.

06:26

Yeah. And say the aircraft has these really clever computers. That makes the art of pressurising and depression areas in the aircraft like totally automatic. Yep. But I mean what would they have done before automatic systems like that? Going back a little bit. There would manually have to pressurise, cabins.

06:43

And even before that, then they just wouldn't have been that option. You just had to fly around it sort of lower altitude. Yes, there are lots of aircraft there, around, pressurised, military, aircraft and but there's general aviation aircraft there on pressurised, and so, whatever. The air pressure is wherever the altitude is outside the aircraft.

07:00

That's the altitude inside the aircraft to state this and so you probably only going to go up to 8,000 feet. Maximum some of these little aircraft, they like DC3 and stuff, you know, used to have to hop over the Alps with passengers in unpressurised. So you'd have to get, you have to find, maybe a lower bit of the Alps, and, but it's gonna be have to be like 10 or 12,000 feet, I guess, which is fine for most people and 8,000 feet.

07:25

If you just sat there drinking Gin and Tonic, you probably wouldn't notice much, but if you ever done any exercise, well no, not really, but I did fly with the Captain once who liked to do some light press-ups in the back of the flight deck. Okay? And so yeah, so if you're a passenger sitting, you're not really physically exerting yourself or mentally existing yourself.

07:45

Then 8,000 feet is fine. But yeah, as soon as you start to exert yourself, particularly physically, it does have an effect. You notice, I notice sometimes cabin crew mode, they've sort of feel a little bit and well, not on well, but just and it's generally because they're up and they're moving and they're working on the lifting and carrying to trolleys, and they're physically existing themselves.

08:05

Yeah. At the top of an 8,000 foot mountain in effect. Yes. So that's gonna be really noticeable to them. Yeah. Because there's ones with step counters. Like cabin crew know that they do, like miles of walking on a fly. Yeah. But like you say they're lifting and walking at 8,000 foot.

08:20

Yeah. It's the cardiovascular system in the heart. That feels the effects of hypoxia first, although the symptoms might be from the nervous system. You know, it's like your eyes and what else is the nervous system things? Are that things that list on the symptom first? Actually your heart say.

08:36

It's all right, if you're sat there but yeah, if you're gonna do some press ups. So you probably won't do as many as you do on the ground. Because once you start asking the heart to pump everything around, just being an 8,000 feet, where saturation of the haemoglobin is 90% rather than 98%.

08:50

You'll actually start to notice that. So what's the most common emergency non normal situation that we have or any pilot? Oh, yeah, medical emergency. Yeah. So any problems that about that you may or may not know about. If I take you up to 8,000 feet cabin altitude you'll soon find out about them, amplifies them, doesn't it?

09:09

Yeah. They're all exaggerated. I mean often have a medical emergency. You might divert. Okay, good. It's all worked out. Well, we've got there person off and then you know in the post flight review, find out that passenger was 98. They had one lung that lung remaining had pneumonia in it and you think.

09:28

Well they're not going to cope very well. Yeah, 8,000 feet. Exactly. And yeah cardiovasc any cardiovascular problems that you might have especially since they're the first that's the first system. Perhaps to be as effective by hypoxia are going to show up and pilots have, you know, strict, screening and cardiovascular system.

09:47

Yeah. And probably for that reason. I guess it's kind of a bit like pregnancy and limits on how many weeks you can be pregnant and then yeah, I find them. I don't think it's because like you're so close to giving birth that like they couldn't cope with birth on a flight.

10:02

Although it I deal, it's more to do with this kind of stresses and strains on the body of being late in the pregnancy process. Yeah. Extra oxygen and physical exertion and you know, your heart is demanding more. So I think that's more why they have the limits. So I'm pregnant when they're flying rather than the fact that they're so close to to their due date.

10:21

It's it's all these things that being 8,000, feet in effect, cabin altitude is going to do to the human body that it wouldn't do at sea level. So it's a bit stupid thing to say, right? But you know, I'm always saying that the best thing about the job and the worst or the worst thing about the job is whoever you're working with say they maybe makes or breaks the job more often or nice.

10:45

The best thing about the job, the person that you sat next to you for eight hours and they're like a total stranger and you might never even see them again, you know, depending on the airline but you end up having quite deep conversations. So you wouldn't have necessarily with somebody.

11:01

You just met. Yeah. Do you wonder if slightly it's because we're slightly drunk like slightly. Hypothetically sort of like slip into you know more. Yeah. Maybe easier why it's funny say that because yeah being hypoxic or slightly hypoxic is similar to the effects of being drunk, you know. And so yeah maybe you know every knows that when they have a drink in the pub this started to become a little bit more loose lips and yeah, maybe maybe there's maybe you've got something in there.

11:29

Maybe you want something, I don't know. But we should be used to it because we're doing it all the time. So you think our physiology would sort of a climatize not literally to it. So, let's talk about when things go wrong. Then. Yeah, so we've got this pressurised aircraft, but what if your cabin attitude starts to climb?

11:47

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Cabin Pressurisation

So very briefly, the cabin pressurisation system. It sucks air. In from the outside pressurises, it pumps it into the cabin. And then the most aircraft have, what's called like an outflow valve, which opens cracks open a tiny bit to just allow a little bit of air to seep out and it just keeps the not closed cylinder.

12:04

No, it's not completely closed. It's kind of almost flows through and keeps the cabin altitude at a constant or climbing or descending depending on on what you're doing. So obviously like old aeroplanes they have other like little areas where air can see power as well. So it's with door seals or cargo door seals or anything really you know, weak spots, basically, where air can leak out.

12:27

So this there's probably two or three reasons why carbon altitude your cabin pressurization system might fail and the cabin al's stupid. Start to rise it could be sort of slowly compression like a small leak but actually the system can't keep up with holding that cabin pressure. It could be some sort of explosive decompression like has been accidents before well like a, you know, a doors blown off or a hole in there.

12:52

A big hole in the aeroplane is caused like a rapid decompression or it could be a failure of the pressurisation system itself failing. So let's split it up like that then say this slow decompressions and rapid decompressions slowly compressions then yeah the pressurisation system fails. Yeah. And it's a complicated system because you using bleed air from the engines to two separate systems normally and then forcing air through this cylinder.

13:19

And then the outflow valve at the back quite easy to spot on an aircraft. And it'll always be open on the ground. Yeah. Because on the ground, you always want the to be no, differential pressure, otherwise you wouldn't be able to open the doors. Yeah. So, the aircraft quite cleverly knows when it's on the ground.

13:35

It must be fully open and it must quickly dump any pressure that it's got left inside. But I did once have a cabin crew. Very rightfully and cleverly who had been fly. I will point out that there was a hole opening in an aircraft. I think it was ours and should point at the alpha valve, which is a giant hole in the area.

13:56

Yeah. Quite right over to like point out something if she thought it was unusual but you can see them at the back, right? Of the aircraft seem to always be there on all aircraft types. Yeah. And they're sort of things that you want closed in a ditching situation, I guess.

14:09

But anyway, so it's a complicated pressurisation system. You could have a failure of that system. I've on a functional check flight, took an empty aircraft up to cruise and depressurized it as part of the check and we put our extra mass on and we see what happens to the cabin oxygen system is on, but you also check the leak rate of the aircraft that.

14:32

It's an acceptable level. Yeah. But the older, the aircraft, the more little leaks you'll have somewhere in the aircraft. So, there's the outflow valve and there's just generally little leaks around. So if your pressurisation system fails the outflow valve, a hopefully will close as quickly as it can to seal you in as much pressure.

14:52

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Sams Experience of Slow Depressurisation

Yes, you can. Yeah, but the aircraft's going to leak out from all sorts of places, and you would assume a new aircraft would have the least amount of leaks basically. Yeah. So I actually had this for real once, so those bleeds air systems that you talk about that, that bring the air in from the outside.

15:07

So, both of those failed are on our aircraft. So we were climbing about 25,000 feet, outside cabin pressure inside. Probably at that stage, would have been about six or seven thousand feet and climbing up towards 8,000. And yeah, so we had no new air coming into the aircraft. So the outlaw valve closed and basically, then, yeah, the cabin altitude started to rise.

15:31

Even though we started to descend basically through the leaks, you know. And I recall, looking at it at one point and the cabin altitude was climbing about a thousand feet a minute. So from 7,000 we knew we had about three minutes for it would get above 10,000 feet and start setting off alarms in the flight deck.

15:52

So are we did a not I wouldn't call emergency descent within a fairly rapid descent from 25,000 feet and we just got down to below 10,000 feet as the cabin altitude was about 9,800, something like that, where we equalised basically and it just just avoided setting, the setting the warning off.

16:11

So, what I was the cause of all this, as this was a, this was actually a dual bleed failure. So there's a bleed system on each engine and by pure bad luck, both of them failed, one, just after takeoff, and we were sort of dealing with that fault as we were climbing up when the second one failed at 25,000 feet.

16:31

And I guess, although that sounds like really unlucky. What was happening was your aircraft was putting a lot of demand on the one remaining. Exactly. Then cause that to fail. Yeah, exactly. So you got down to 10,000. Why 10,000? That's that's the kind of accepted altitude that there you know, there's breathable and you got useful consciousness but also that's what the aircraft sort of trigger is for setting off the alarms to tell you that you're going to put 10,000 feet cabin altitude.

17:05

I think it's actually 9,800. I think it is actually I think this is really annoying. So why remember is it was it was it was the actual cabin altitude was flashing like 9,700 or whatever it was. So it was given me it was given us the advisory that it's you know you're getting very close here basically.

17:22

But yeah I think I think it's 9880 or something like that is where the warning actually goes off. The 10,000 is higher than the 8,000 were normally used to find out. Say vulnerable people with health conditions or elkly people might not do that well at 10,000 but they're probably survive while you sort out the problem.

17:38

Yeah, but let's let's think about this. So you needed to do not an emergency, you decided, you try and beat the cabin out to you now. So, trying to get down them before it went above 10,000. Exactly. But what you know, what can you just send to 3,000? Well, because of where it was.

17:54

So as this is an old airline, I used to work for, we were in Malaga in the south of Spain. So not the worst for terrain, but there's some fairly big old hills around Malaga and Granada. So our MSA, our minimum safe altitude was actually above 10,000 feet from where we are, so we could start off our descent quite quickly, but then we needed to get our charts out and just figure out exactly where we are in exact get to somewhere that we knew was safe to go below 10,000.

18:20

Okay? So we wouldn't hit the mountain. That would be terrible. Shame to have, you know, saved everybody from hypoxia and death, but then, ploughed into a mountain. Oh, yeah. But I mean, why that is one of the reasons to climb the aircraft. Like we said about getting everything else.

18:34

A yeah, trains always in the way, isn't it? And whether and traffic and so on because you just stop, you making a quick to send what about a cabin crew, what happened with them? So not huge amount they called us first actually. So as we were starting the descent, they obviously noticed.

18:49

Hey, you were supposed to be climbing back towards Manchester now. Why are we descending back towards the ground? As I think they called us first and we briefly just explained what the issue was. However, they had no indication in the cabin that there was a problem with the oxygen because the cabin oxygen masks don't drop down to actually 14,000 feet cabin altitude.

19:14

So actually, we never got anywhere near that. We never triggered the masks in the cabin. They were only aware of a descent basically say, call us. That's interesting. Let's come back to that, then cabin crews procedures because they're very involved in emergency descents, they're part of the procedure so you had a slow decompression.

19:32

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Rapid Decompression

Yeah, exactly. You said that there was such things a decompression. Yeah, there's some quite like you leaded to you, dramatic accidents, which began with rapid decompressions. The one I can think of is where there's that 737 with the whole top of the aircraft missing that was like in Hawaii, wasn't it?

19:50

Aloha? Yeah. Yeah. I mean that was just crazy. Yeah, Aloha 1988. Unfortunately. Well, the crew did really well the but one person died, which is one of the cabin crew. She was stood up when the decompression happened and was it metal fatigue? I think and then weeks, oh yeah, a whole of some size opened up in the aircraft and then the cabin crew along with probably lots of debris got sucked towards that hole.

20:14

And then makes the whole bigger impact of that actually made the whole bigger. Exactly. Yeah, following that cabin crew were trained and just generally became where if you hear a loud bang that you dropped to the floor and hold on to something. Yeah, even in that Sioux City podcast, we did.

20:29

That's what one of the crew did when the engine failed was instinctively just hit the floor because it's that was cabin. Crew that died in that accident, but this the picture of that aircraft is amazing. The Aloha. Yeah, you've got the captain who got partially sucked out of their aircraft British airways 1990 out of Gatwick, I think.

20:49

Yeah, Gatwick and they diverted, in Southampton, I think. Is that right? Yeah, yeah. So it's amazing story behind that but they basically not put the right bolts in the windscreen and say that that blew out and so they had explosive decompression right in front of the captain. Yeah, he was half sucked out and would definitely look at that another time.

21:07

Yeah. That's probably a good accident to look at in the whole podcast. Really. There's even I think a Qantas flight where the oxygen cylinder that provides emergency oxygen to the flight deck, blew up and close and explosive decompression. Well the coke can analogy is imagine a can of coke that you shake up.

21:23

So I know you may really violently. Yeah. You want to drink. Yeah, yeah, open this. Yeah, that coke can is basically one, aeroplane is flying through the air. It's like highly pressurised and the different pressure pressure between the pressure inside that coke can versus outside. Yeah. In normal, air is like huge.

21:40

So you were to pop a hole in that coat. Can I either open the lids or just stabber? What used to do in school, stab a compass in it? Or you did? What about those Americans on videos now that like, bite into it or something? I don't know the drink.

21:54

Yeah, maybe you should. Yeah, but as soon as you like, pop a hole in that, everything's just gonna fire out of it because it's trying to equalise the pressure. Basically it is a good analogy because yeah. Yeah thin aluminium. She basically diffused. Like, yeah, but the physiological effects then of being instantaneously taken from 8,000 feet cabin attitude to the outside because how long is it gonna take like seconds?

22:20

Yeah, there's a face to the gradual decompression. We're talking about in one or two seconds or something. This amazing change in air pressure. So what are the physiological effects? Well, there's one way I could put it which is what a train. It wasn't said to you and me on our MCC course, right?

22:38

I think he said something going lines of it's like having two red, hot poker sticking your eye, two red hot poker stuck up your nose and one red. Hot poker stuck like somewhere else where you wouldn't really want it. Yeah, and that's how he described his experience of when he had an explosive decompression.

22:55

So he's saying to pain the pain from those orifices. Yeah. Yeah. You know is that intense? Because the space, your body is full of gas. Yeah. So it just wants to leak out is once. Yeah. So if you've been holding in politely, something. Yeah, this coming straight out. Yeah.

23:10

And unfortunately, gas is gonna leak out through what did you say? Your eyes and your ears? He said eyes. No, but he said the pain from like your eyes, right? Okay, I guess this. So, how was that gonna do if you're trying to fly? Yeah, crazy. It's gonna be crazy, isn't it?

23:23

It's gonna be insane. I mean, the crew often tell you like some really unhealthy job and you don't know what they're really into and they'll point out their water bottles that you've taken from sea level. And then you've had a drink and close the lid. Go up to 8,000 feet and will expand.

23:40

And then as you start to descend all like contract and say, what must be happening? Just gently sector after sector to your organs and stuff. Like, I know it's probably not great for you but it seems to be, alright. But if you have an explosive decompression then you know, that's, that's pretty.

23:56

You know, what about didn't you take your girlfriend to the dentist and oh, it's explained aerodontalgia. Don't tell you yeah yes. So she always used to get pain in her teeth when she used to fly. And I think it was the dentist that when she explained it, the dentist like, oh yeah, that's aerodontalgia.

24:17

And basically where she'd had a filling and there's a tiny little sort of gap. Underneath the filling, whatever she went flying in an aeroplane that air that was trapped in. That tooth was still look kind of sea level pressure. And so like the fizzy coke kind of allergy. So really high pressure air inside her tooth.

24:38

Yeah. Basically, wanting trying to escape and get out and nasty. Yeah. She just used to get really bad pain in their teeth. Yeah. So you can see like some of the effects of the rapid decompression are going to be. I mean, we have dangerous part of our dangerous, goods lists of things we can and can't accept on the aircraft, obviously, certain pressurised things we can't put on the aircraft like you know all like Ross from friends on that episode he's nicked all the shampoo from his hotel and then when he gets back home it's all exploded in his major shampoo explosion in his suitcase and he's annoyed.

25:10

And that happens or like crisp bag. So is explode in the flight there which causes high minor alarm and you know how a lot of pilots have a little piece of paper which they write like the flight number on and their time of arrival and useful information. Why I don't do that.

25:26

People will think I'm a bit weird because I'm like, the only person who doesn't stick like this piece of paper to the instrument panel. But I always think like, even in the MSA on there great. But as soon as you have an explosive decompression that's going, it's got the first thing, our window.

25:39

Like also you get you know when you come you do a little bit of plane spotting, you see, in aircraft coming into land and you have that low pressure area above the wing and you get this beautiful instantaneous fog that appears. Yeah. And disappears due to the pressure difference.

25:55

Well, I believe same in the flight debt or in the aircraft. When you ever rapid decompression, you can have this sudden fog. Okay, appear. And even the instruments can have frost appear on them. Yeah, so I don't know what you reckon the first few seconds of an explosive. Yeah, these just crazy.

26:10

It must be crazy. It a us and say you've got memory items to apply in that moment. Yeah. And you've got what's the time of usual, consciousness, at 40,000 feet lights, but 10 seconds. 12 seconds? Something yeah. So you've got 12 or 10 seconds to put your mask on.

26:26

Yeah. Otherwise it's game over. You'll still be conscious but the chance of you doing the right thing. Yeah, you become like so. So drunk that you just can function, basically. That's the it's kind of the effect that hypoxia that quickly. So that's like that only thing anybody ever needs to remember about oxygen.

26:42

I don't care about anything else. The only thing any pilot needs to remember is that right next year, you've got this flight deck oxygen system available to you and you can just done your mask at any time and you'll be protected. Yes, the rest of the cabin might be in chaos and the passengers need to get their oxygen.

27:00

You're gonna have to descend the aircraft, but that can all happen in a slow calm time. If you don't have your oxygen mask on this game over, it's like the only thing you need to remember. But you can always to take off, can't you? Yeah. So if you ever put it on you know, what's the saying you if there's any doubt there is no doubt if you think that there might be some kind of decompression situation happening, maybe you've noticed something with your colleague or you just lost SA, yeah, just put your mask on, right, you probably never seen anybody do it, but I'm just saying, somehow get that ingrained in your mind that no one's gonna tell you off for doing that.

27:36

It's a slight tangent, but yeah, pilot incapacitation, if your colleague becomes incapacitated, even though it might not be obvious or there's nothing telling you as a depressurization or something through the oxygen. You one of my first thoughts would be do I need to be on oxygen? Is it is the first thing on the checklist consideration?

27:54

I don't think so. And I oh it's a really good point but it's something I don't think is on the checklist. Yeah. Because you don't know why they've become. You know, what exactly it could be like a loosely related to hypoxia like toxic hypoxia could be a fumes event.

28:08

It's not affected you miracly, you know. Yeah. Different people have the effects of hypoxia happen in different order for different people and also different ages and so on. So if you're the lucky one that gets to spot their colleague having incapacitation then yeah, she definitely think of the mask and you can always take it off is what I'm saying.

28:26

So you might decide, okay, we're actually safe and, you know, say definitely not pressurisation. So take a mask off. Yeah, yeah, time of useful consciousness. There's tables. It's going to vary person to person and so on, but you just need to be aware that exponential decrease, and the altitudes that we operate airliners are it's incredibly low, the time of useful consciousness.

28:46

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Kalitta 66

So, right sound. So I'm going to play you some piece of audio. We're just going to listen to it. Okay, talk about after. Yeah. I don't know anything about this. Okay. Right. Okay. Somebody read different sounds. Interesting

“Kalitta 66, Cleveland out here.

29:20

There, he's declaring an emergency with his flight control. Yes, sir. He said affirmative on that, right? Kalitta 66 Roger, what? Your intentions request vectors ypsilanti .

29:46

There is looking for vectors. All right Kalitta. 66 understanding the emergency. You want to vector to Cincinnati. Is that correct? Which is inflammatory. Beautiful landing, Kalitta 66. Are able. Are you able to maintain altitude? What what assistance can I give you other net? Vector and able to control altitude.

30:16

Unable to the control airspeed, unable to control altitude,unable to control heading.

30:31

Everything. A-OK. Okay. Kalitta, understand. You're not able to control the aircraft. Is that correct? That is correct. Kalitta 66. Are you able to able to land an airport airport that is closer to your position? Pittsburgh approximately now, southwest your position, Cleveland about eight miles, northwest your position.

31:03

Prefer aircraft destination airports and aircrafts is no damage to any more of the aircraft. So always ever so slowly with regaining. control. And if

31:45

Whoa, Kalitta 66 is able to send and maintain flood level. 260, they have to play two zero, let a 66. Are you still requesting a vector for a Ypsilanti? To the right of Kalitta 66 area. Precipitation 11 o'clock and one five miles extends, approximately threesome reflect Looks like and Roger 11,000 + 66 quoted 60, six.

32:54

Roger say, say intentions. Definitely anything plus 66 Roger Clear Delia Salini via direct maintain improve contact.” So would you make that? That's amazing. I've never heard that before, and that's incredible. So, what was happening? Well, obviously, it was hypoxia and but I've never, when, when did you get to that?

33:49

And well, I kind of had an idea that we were talking about oxygen, that maybe that's why you you'd played it, but I've never heard or seen hypoxia in action, really? Yeah, I just sounded drunk basically. It's like a drunk guy. Yeah. What's your favourite line? Everything say oh okay yeah I know apart from like the funny control heading altitude and what's interesting is that the the second pilot came back towards the end there so you could assume that he was maybe like unconscious possibly or just completely out of it.

34:25

Unable to key the mic to like press the microphone or whatever. Yeah. But then they both come back towards the end and they just sound like normal. So let's let's talk about what happened briefly say and it's a little charter company Kalitta and the flight is clear, six six and it's 2008 and it's a learjet 25.

34:46

The aircraft is gradually slowly depressurised not rapid decompression. So slow decompression, the pilots have become hypoxia and one of them is talking on air traffic control is saying that they've got problem with their flight controls in the face of other aircraft trying to relay and saying he says he's got a problem with his flight controls after a while.

35:07

One of the air traffic controllers works out that they think he's hypoxic yeah and so they managed to convince him to descend. Yeah. And as they descend into air with a higher pressure of oxygen, the effects of hypoxia on seemingly, both of them but one of them first just instantaneously wear off.

35:26

Yeah, I think one of the things that contributed to saving them is the or pilot was disconnected. And so they were able to sort of just tell him to do descendants. He's kind of went for it. Yeah, like a lot of accidents. Thanks. Unfortunately, to a serious accident with loss of life, many more people are able to, you know, have their lives safe because what we learn, and this is a good example of that.

35:47

Because it was the same aircraft Lear, jet 25, suddenly and accidentally 1999. And where the pilots were hypoxic in the aircraft crashed is actually with the famous US open champion Payne Stewart on board and from that the air traffic control, had some kind of training or awareness about hypoxic pilots and picking up the symptoms.

36:06

So the two air drive control. Is there the one you can hear which is Marvin. Marvin. McCombs and Stephanie Bevans were got awarded for their for saving. The saving serious accident by recognising hypoxia here but what an awesome, you know. That's right. But yeah party really powerful example that like said I've never heard that before is.

36:28

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Emergency Descent

Yeah, it does incredible. So talk to me about emergency descent, what, what's the outline of them? Yes, and emergency descent. So, this is going to be following one of these rapid decompressions that we've been talking about. Does it have to be? Yeah. After, can you mention any time I guess?

36:48

Well, yeah, I guess so. Yeah, it's no reason why you couldn't, but it would typically be it be if the cabinet is above his plan or is uncontrolled or uncontrollable. Yeah. So some useful consciousness, we talked about very small. So first action, protects yourself, get your oxygen mask on.

37:09

And then the next action is really are about descending. The aircraft into richer air, oxygen richer air. So starting a descent and helping to speed that descent along with maybe some extra drag speed breaks or possibly landing gear depending on limitations speeding up. If all of, it's not such a big structural damage.

37:33

So just basically getting the aircraft down as quickly as possible. However, there are it's not just as simple. As, as you said earlier, this end is 3,000 feet. There's all sorts of things to consider as well as controlling the emergency descent and everything it's going on. Within the aeroplane, you've got to be aware of what's outside the aeroplane and where you're descending to and where what sort of airspace you're over who, what other aircraft might be around what?

37:58

Terrain might be around. Yeah, so we always sort of thing, fly navigate communicate. So they're first actions of the emergency descent our memory items and the very first action almost, I want to say it should be an instinct. Now, memory item to put your mask on. Yeah. And then compose yourself to start the emergency descent, which is a two crew thing.

38:17

Then you've got navigation, there's gonna be weather terrain other aircraft and communicate to air traffic control that you're doing this descent through all of their layers of airspace. Yeah. And what kind of rate descent might? We I think probably like if everything and your favour could probably go up to 6,000 feet, a minute, maybe.

38:34

Yeah. Yeah. This is a lot, which is a nice rate, but occasion to where I exceed 5000 feet per minute in a normal set. Yeah, yeah, maybe more. Yeah, so you look there, I mean, I must say necessarily get more, but yeah. Yeah that's capable easily capable of dinner, six thousand feet per minute.

38:51

Six a minute from 36,000 feet. It would take you six minutes to get to sea level basically. Okay. So maybe sort of four or five minutes to get to flight level 100. So it took about masks, then you talk about cabin oxygen systems earlier on. Yeah. That they're very different to what the flight deck have.

39:08

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Emergency Oxygen Systems

Yes. How does their cabin oxygen emergency? Oxygen supply work. Yeah, so the cabin oxygen masks the drop down from from overhead. They are depending on aircraft type, would be triggered at a different point but on our aircraft it's about 14,000 feet but they're not pure oxygen. They're like, it's like a chemical chemical reaction.

39:29

Basically, which are oxygen into their oxide. You, when you pull the mass towards you, it's our first thing in there. Safety video that starts looking for the pin out, which starts these two solid chemicals. Combining in one of the byproducts is oxygen. Yeah, which is what you want. The other one is heat.

39:47

Yeah. So I think it gets quite hot. Yeah. I've heard that, but importantly, what you are saying is that those masks will fall down of their own accord. That system is independent. If the cabin attitude goes above, 14,000 feet on most fleets, right. We can manually put them down. Or if you do a really hard landing, a couple of them might fall down.

40:09

Yeah, because they are, you know, they're just sort of ledged there. Yeah. Ready to drop? Yeah. And but they should drop automatically when they're cabin altitude is, you know, let's say, 14,000 feet or above what the cabin crew gonna do, when, although sudden the mass drop. So when the mass drop that should be the first sign to them that something's wrong with the oxygen system, just so if they aren't feeling the aircraft descending at that point then there's a possibility of the flight crew and not aware of a problem so they would probably want to protect themselves.

40:42

First of all get themselves onto some oxygen and then contact the flight crew to see what's going on. Basically did have to give the flight crew a little bit of the chance to get their own oxygen on and start a descent. Typically probably a mint, 30 seconds, a minute or so, maybe a little bit more, but if they're not, if they're noticing that the aircraft's, not descending after 90 seconds or so, I think they would then begin on to contact them.

41:03

Yeah. Say be laid down in their manual, specifically. And it's actually mandated by your aviation agency. Probably worldwide that they have to be part of this procedure. So if they see the mask come down, they have the same masks as there, passengers. It's the same one that they do in the demo.

41:18

We pull, they pull them towards as they have them in the toilets in the galley, with the little bag. Yeah. Because this is a chemical reaction, it just starts producing oxygen. So, if you're not breathing it, it just fills up in the little bag. That's the whole late thing and then they're going to be part of our procedure.

41:34

IE, they're going to come and check that we are alive or aware of the situation, excuse me. If we haven't started a descent and probably made a PA saying everybody get on oxygen. Yeah. Okay so in the flight deck, very different system which we've talked to a little bit about.

41:52

Yeah, but that's oxygen supplied under positive pressure. So when you breathe in, that's when the oxygen is supplied to you. Yeah. Just rewinding slightly the cabin system. How long does that last? They recommend 15 minutes don't they? Yeah, the minimum of 12 is it over 12 but sure, yeah.

42:10

Typically that's what's the difference on long haul, you might not be able to get down quite so fast, depending on where you are, if they're placing the world where the mountains are. So, the train is so high. That you might actually be intermediate levels for a long time, escape routes and drift down procedures and things.

42:27

Yes, I guess. It's not sure how long a whole thing. It's if you're in Europe, if it's a. Yeah. Exactly. But yes, Central Asia and Greenland there isn't anywhere for you to be able to get to 10,000 feet within 12, or 15 minutes. Yes. You have to have a cabin system that can supply oxygen to passengers.

42:45

While you first probably get down to like 20,000 feet. Fly. Some complicated route called oxygen escape route. There's laid out in a chart down a valley to eventually get to the closest place where you can then descend down to 10,000 feet before the cabin oxygen system runs out. So sorry.

43:04

Going back to the flight there oxygen system, that's totally different. Yeah, and depending on what setting you have on your on your mask because it's designed to provide positive supply of oxygen either a hundred percent or mixed. Yeah. And depending on what you said, like depends how long it lasts and how many people are in the flight deck.

43:23

And so on. Because we also use it like we've already said in fumes and smoke situations. Yes, not just for decompressions and don't forget you. Preflight, checks are pretty important. Remember in British Airways 09 is that the we've already done in a podcast, the Jakarta we're all engines failed.

43:41

Yeah. So they start filling up with kind of sulphur smoke. So, decide oxygen on the first off to play his mask on, on the hose wasn't even connecting. Yeah, that's right. So, they decided to do a descent to get, some outside air breathable air, which coincidentally happened to save them.

43:59

But anyway, just one more oxygen system, a therapeutic oxygen. What's a most airlines will carry all? That's probably will carry some therapeutic oxygen and so that's to be used for inflight contingencies, you know, somebody falls alien flight. I think people can pre-order it as well possibly. If you've got a medical condition you can have it pre-ordered through your doctor that you're gonna use the onboard therapeutic oxygen to help you through the flight.

44:23

Yeah, therapy, say it as the title suggests I guess it's for medical. Yeah. Reasons either exist in or you know, things that can't fly but can be used in decompressions. Yeah. How would you use that if you? Because it's portable basically. So they can use it to move about.

44:41

So it just be the oxygen cylinder with a mask attached to it. And so, once they've maybe got over the initial rapid decompression, whatever that might have been, where they've jumped onto a one of the passenger oxygen masks. They can actually, they always talk about how they would like, sort of monkey, swing.

44:57

Yeah, between mass to mass to mask. It's really so they got to the galley and we're able to put on a portable oxygen bottle and because they're not nicking the passenger ones. No should be a spare one in each row. I think this is a row of three four four masks, right?

45:11

Yeah for infants and children stuff. Yeah camera. We've got to come in potentially in a D pressurised, aircraft to check. We're okay. And so they would do that on the therapeutic oxygen. They can change the flow rate and then last a while, and you've always got a load of those bottles on board, which part of the MEL?

45:27

Yeah, this is something like cabin crew number of cabin crew. Plus you something oxygen bottles. So yeah, quite a lot. So fit your own mask for helping somebody else advice. Yeah, because, you know, you're useless to anybody and you never they're never gonna get their oxygen. Say going back to protect yourself.

45:48

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Helios Airways 522

First. Yeah, always put your mask on. I think we're leading towards an obvious accident 2005. 2005, August 2005, helios five. To two is what we're gonna talk about. And so many lessons learnt from these accidents. Look at that collider. And and and say, by studying these accidents, they shouldn't have happened.

46:10

We can prevent them from happening again. Definitely a lot lent from this one. So this what the second for Boeing 737. We're going from Larnanca in Cyprus. Yes. To Athens. I think it's gonna get a Prague. Yeah, both stopping in after Athens. Not the longest flights. Then, no, the crucity a couple of hours, the aircraft had some previous pressurisation problems, which they've been looked at by the engineers, but somehow whether intentionally or by mistake, I don't have it.

46:41

My nose here, he'd left it in manual mode. That was my understanding, so rather than this, automatic pressurisation system had been left in the manual mode which means that the pilots would have been required to control the pressurisation themselves. So just to be clear the aircraft that was its own pressurisation, but if you've got it, if you've got a switch set to manual, you're telling the aircraft don't.

47:04

I will control the outflow of valve valve. Yeah. So the automatic aircraft won't pressurise at all or won't changes settings. It's all. So it had em. It had a history of potential, pressurization problems and door seals. So how common is a door seal issue? Yeah that does that happens quite a lot you quite often, get I find cabin crew will call and say, oh, it's a whistling noise by the door and you go out and yeah, sure enough.

47:30

It's sounds like a seal gone. Possibly on the door, a little bit doors, get open and close all the time and then there's all crap on the floor and the cleaners are coming in and out. And yeah, they are really well designed doors and on Boeings, aren't they all plug doors?

47:45

Yeah. Go in and then plug, but not on air bus but there is a rubber seal, basically, at some point, like, you would expect to seal the door. And if there's something caught in there or the seals, the t-rated, differential pressure is quite high. So you certainly get this horrible high pressure squealing where the air is leaving, but that's okay.

48:04

Because as we said, it's not a closed cylinder but it's something that needs to looking at. So it definitely had some of these issues if not other issues with the pressurisation system. Yeah. And say there was a British engineer stationed in Cyprus, nice custody job for him. Aircraft comes in, does a check on it, you know, daily nightly sort of check and looks at any problems.

48:24

So while the aircraft have been sat there overnight, he's ran some kind of authorised procedure by the book, probably to pressurise the aircraft on the ground and then go and look for leaks in the way that Boeing of exactly told him to do that. Now whether or not he didn't follow the last line of the procedure.

48:42

If you like, I don't know, I never got to the bottom of but I think it's established that that engineer did leave the switch in manual. Yeah, you would assume the procedure the last line of procedure was set it back to auto but okay so the engineers left it there in manual and then these two flight crew have take it from Larnaca to Athens.

49:02

Yeah. So I think the cockpit setup in a bowing is that both pilots for your PF or PM have certain systems overhead panels. And switches are your responsibility and on that day, okay? It happened to be the FO who would have gone through the pressurisation panel, but it's like a rotary switch.

49:22

Yes. Like I'm trying to describe. This is not a button. No, it's like a cooker, right? On a cooker. Right, right. Okay. Say it probably have like auto two and manual, you know, it was in manual. So I don't know how many times did the FF seen in manual?

49:37

Yeah one probably never. But how easy would it be to spy? Don't think it would be. That's really interesting human factors problem. I mean in an air bus, you have this lights off philosophy, which is really clever which is if the overhead panel is set up. You know, a normal configuration then this just no lights.

49:56

No lights. Yeah. But if you've left one of them off by mistake, then you'll see it straight away because it's suddenly a bright light on. But this wasn't the case here. So expecting a human to repeat the same action for however, many thousand flights they'll do in their career and even though 999 times out a thousand that switch will be where it should be in auto, your brain is going to get is, doesn't want to check it because it's like, why would I, you know, it's not your conscious mind.

50:27

Your unconscious mind is trying to save energy and I don't want to check that switch. Yeah, so in on one hand you might it might stand out in my life because you, like, hold on. That's which is definitely in the wrong position because I've seen it 999 times in the right position, but my point being that also, if you don't have the rigour of looking.

50:45

And what's the saying like looking and really like checking what? You're looking at the output basically. Yeah. So they took off with the aircraft pressurisation system manual. So what happens next? So they start to climb basically and the cabin altitude was basically the same as the outside altitude and passing 12,000 feet.

51:08

So must be slightly different on the Boeing. They got the first alarm went off saying problematic, cabin, altitudes at 12,000 feet. This is the first and probably the most unbelievable like Swiss cheese element to. It was that that alarm was absolutely identical to another alarm which is a takeoff warning, config alarm and the crew just assumed that it was a spurious.

51:32

That's what an alarm. They might have heard a few times before, possibly in the simulator or as even one they would do every day, like to check. Yeah. Possibly, they'll have heard it. A lot and bearing, it's actually like a horn. Yeah, the exact noise at that horn is for two separate.

51:48

Totally separate things other things. But you would assume, I guess, the design of the aircraft thought. Well, if it goes over 12,000 feet, it's not a takeoff. Config. Yeah, the mind doesn't really work. like that. So they assumed because they heard it before as a takeoff warning conflict, that it was a spurious, takeoff warning, config and just saying that's going off at 12,000 feet.

52:08

So what have we learnt about oxygen? Yeah. So already possibly. They are slightly least potentially in the early stages of very early stages and they're climbing at. What? In 2000? Feet a minute. Yes, it's getting worse. So, yes, they, they kept climbing and then they eventually spoke to engineering, and it was actually, the engineer that had done the overnight work on the aircraft that they spoke to in how they how they call engineer.

52:33

So they'd be calling me on, like, what we call box two like VHF channel two. Because busy that all the time. Like, talk with range. Yeah. Talk to call the engineers. No help you out. If you go a little problem and I guess if you've got satphone, you can do that anywhere in the world.

52:47

So they call the engineer who actually on the copy voice recorder. He actually asked them to check the cabin, pressure mode, whether it was in manual, but the report sort of said, that hypoxia had already set in and the captain, basically disregarded that question and asked about something else because what it was the avionics computers also sit in the pressurised aircraft and if the computers are in air which is unpressurized, the density, air is obviously much lower and so you need these massive fans constantly calling these really old computers basically in the avionics bay and they were the first things to sound the alarm, which is like they had an avionics heating problem.

53:32

Yeah. Because they're not getting enough air to call them down. So the captain was on the radio to the engineer saying I've got an avionics cooling problem. Yeah. And where am I CBs for the avionics cooling. Okay. And the engineer really cleverly, realised, that he may be confused and that's why I was advocating for him to check his cabin pressure and there's another little nuance here, which is you know, like the riga of small detail of how you should apply procedures.

54:04

So in our aircraft, if we have a master caution you should cancel the alarm and then you go about okay, what's the master caution? And yeah, and dealing with it and doing that all very systematically, but the very first thing you cancel it because as the way I understand it is, then if another failure occurs, the master caution will light up again and you'll be alerted that there is another failure.

54:27

Yeah, so the CVR for this accident is only 30 minutes of the of the flights. It doesn't go this far back but there's a possibility that when they got the avionics cooling caution, if it wasn't cancelled properly, then when they got a caution for the masks cabin masks, they wouldn't have seen it because I was hiding behind the caution, that was there.

54:51

Yeah. Well, and so just how, you know, a small discipline of things that the aircraft designers built in, you have to follow otherwise you open up more and more holes in the cheese. If you like, yeah, for these accidents to get three. So he's got Avionics cooling. He thinks and there is criticism in the actual report.

55:11

The non technical skills of the pilots there, which is really difficult for me to. Yeah, you know, criticise it's hard, we don't know when they became hypoxic, but there is that point isn't the way. You think you've diagnosed a problem? But you've got this has on the backyard or this uncomfortable, feeling that I've misdiagnosed a problem, and that should be a red flag to be like, let's go back to basics.

55:34

And, you know, is this an avionics cooling thing? There's one alarm, but it's not coinciding with this. But, meanwhile, what's going on in the cabin? Yeah. So the masks dropped in the cabin, cabin crew, passengers all using their chemical generated oxygen masks, but obviously, the aircraft still climbing. So I don't know why.

55:52

The cabin crew wouldn't have approached the flight deck earlier. Yeah, I don't think it was one of their procedures, no, one of their procedures but sadly for those poor passengers, their oxygen is going to run out in 15 minutes which is obviously what happened. Then they start breathing just outside air which is by now, almost cruising altitude probably 30th.

56:13

You know, they have seconds of useful consciousness and probably minutes of actual consciousness before everybody just passed out, basically, because you've got this tragic situation. Imagine if it was in a well, it is in lot, entries. And they call it like the ghost plane and stuff, but just before, it's really all over.

56:31

You've got this tragedy of. If you look behind the flight deck, door, a cabin full of all of the passengers promptly, put on their extra mass and been told to sit down and put their oxygen masks on by the crew, and they're breathing oxygen from this amazing chemical generated system.

56:45

And on the other side of the flight deck, door, you've got a total missed diagnosis of what's going on and pilots here, quickly become hypoxic and then lose consciousness. So the pilots in the flight, deck loose conscious the aircraft's climbing. It really high rate was cleared to climb to its cruise altitude.

57:02

Unfortunately. Yeah, 37,000 feet, I think and in the back patiently waiting is the cabin crew and the passengers for the pilots to do something. So it reaches its cruise altitude. And then the pilot string capacity is. So there's a loss of comms situation with air traffic, control and air drive.

57:24

You know, loss of comms is like reasonably common. I've even had it in that part of the world of had, you know, a few lots of cons. It's not always, you know, some massive tragedy, but the air traffic controls, don't follow the absolute correct procedure when the aircraft transits from the next ATC.

57:42

Based into Greek airspace, you know, the controllers are saying, here's my blip and you're now in control of this radar blip on the screen. It doesn't tell. Well, tells them, I'm having difficulty contacting them, but doesn't initiate a loss of comms procedure handover, which might have changed the situation.

57:59

But merely they climate thousand feet level off and continue on their navigation towards towards Athens and then the Greeks realise something's up and say what do they do next? It's point of which they send the military fighter jets up to intercept them. I've never been incepted but like they get pretty close.

58:21

I think these fighter jets. Well, I'm sure I read in the report they got so close. That the the fighter pilot could see into the flight deck. I mean, that's incredible for travelling like 500 miles an hour, how close you got but you could see the pilot slumped as the controls through the flight deck.

58:37

You could see all the cabin masks deployed. Yeah, as well. Yeah, you know, they are they love it. They can intercept like incredibly close and they are looking for hijack situations. So again, if you like looking really carefully but yeah, as I understand it, you can see their eyes, like, that's how place they are.

58:54

Yeah. So what's happening? I mean, basically brain damage is setting in there, say hi. These guys have been unconscious that now essentially dead already. Pretty much. Yeah. And the aircraft's flying along happily towards Athens and it gets to Athens and then goes into the missed approach. Hold. Yeah. So it doesn't descend ever is 37,000.

59:14

Feet doing exactly what the MCP pilots put in climb 37. Stay in nav mode and it just goes into the hole over here. Yeah you know KEA hold. Yeah. Yes I think it's an island. Is it to the south of Athens with a VOR on it. And there is and the you know, you've got this f16 following the aircraft, you remember what happens next?

59:33

So I think that at some point, one of the cabin crew is actually still conscious so one would assume he's been on therapeutic oxygen which lasts a lot longer. He actually gains access to the flight there. He eventually must realise something's wrong here. Like you know, this has gone on too long and actually gets emergency access into the flight deck finds the pilots slum to the controls tries to put their oxygen mask on to no avail.

01:00:00

But by this time times running out because basically the fuels running out. Yeah. So he takes the captain out of his seat. Yeah. And we don't know, but possibly applied oxygen to the captain. Yeah. How obviously, as well as probably the first officer as well. And eventually is seen by the F-16 pilot.

01:00:18

Yeah. At the controls and he could see that it's cabin. Crew, wearing a cabin crew vest but this guy isn't just any cabin crew, no. Didn't he have some sort of pilot's licence? Yes. Commercial parties licence yeah from the UK, right? So this is great, right? But the next thing that happens, two minutes after to not see the left engine flames out due to fuel starvation, and then four minutes later the right engine to dual engine failure, and some cabin crew of CPL is at the controls.

01:00:50

And probably this guy is hypoxic, yeah, because why he wasn't in the flight deck earlier? Yeah, when nobody's sure. But potentially, he was hypoxic and managed to kind of convince himself to get on therapeutic and started to revive himself, possibly certainly, it's hard to know exactly what happened but he tried to make four made a call on the radio.

01:01:14

And you know, what would he be able to do then if he, you know, say before before he ran out of fuel, you know, directly he could land it. I think he'd have a better than even chance. Probably, if it was no issue. I think a fully serviceable with the radio craft with a radio with some fighter jet help.

01:01:33

Yeah. I think story it would have been yeah. He'd like the total opposite but he transmitted a mayday on the VHF one frequency, which was like he is, you know, you have a few hundred miles back so nobody heard it. So I think he probably was hypoxic this gentleman his fiance, was cabin crew and she was on board too.

01:01:57

Now, the F16 pilot, there's an interview with him which is makes difficult to watch because he he's very upset reliving. This guy had to escort this aircraft as it ran out of fuel and just ascended towards the ground and totally helpless. I mean, this horrible and you can watch the head up display on the internet and you don't really get see anything, but you can hear the distress in there, F-16 pilot, it's voice.

01:02:28

Interestingly, they the cabin crew, that was at the controls is a bit of a hero because it's proven that he disconnected the autopilot, or used heading and turned away from Athens or built-up area. And as the aircraft like sadly descended towards some hills, he was making positive inputs to the controls of the whole time, right?

01:02:55

Up toimpact. And looking like he and to sort of do a control crash, but the aircraft in a dual engine failure, the 737 goes into like a manual backup made. So the controls are extremely heavy. This guy's hypoxic, you know, and it's the aircraft crashed in such a way that it was totally destroyed apart from the tail section, which has the helios god of on the tail, which sort of stood out, everything else was totally destroyed, destroyed on impact, really, sad and difficult accident.

01:03:27

It's obviously captures a lot of people's attention and is plenty of documentaries, but so much was learnt from it. So,, some mandated that cabin crew procedures have to be that. If there is the cabin, any signs of decompression or the cabin, oxygen system is activating the masks fall down.

01:03:45

The cabin crew, have to go into the flight deck. If they don't, if they're not sure that the flight crew are dealing with it. Yeah, which obviously would have saved this Boeing. How to redesign, I think even retrofit some of their cabin altitude warning systems, so that there's less.

01:04:01

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Ending

So there's no chance of confusion about what alarm was going off. And, did you know that in Sweden? Just a few years later taking off out of Stockholm at Bremen, there was an RJ, Avro RJ, jet that took off and part of that. I think de-ice in procedures whether you turn the packs off, right?

01:04:22

So these pilots took off with the packs off and the aircraft never pressurised. And so essentially a slow decompression as they climbed. And again, the cabin oxygen system, activated independently in the mass came down and everyone put their oxygen masks on. But this time, thanks to the lessons learnt here.

01:04:42

The cabin crew went into the flight deck and you know what they were doing, they would troubleshoot in the exact same thing. They were troubleshooting avionics overheat and had no idea about the cabin, pressurization problem, because for some reason, no alarm went off. But luckily, because the cabin crew came in and the flight crew probably looked behind them and got to see, you know, the oxygen masks and so on, they started emergency.

01:05:04

And and and thankfully like, however, many lives were saved because that, yeah, it's funny that in some of these accidents, you know, like the shell model. You know, the pilots have some information and the cabin crew and the cabin has other parts of information. The system actually had a complete picture of what was going on but it didn't all arrive at the pilots in the helios crash for them.

01:05:26

Say, you know, able to do anything about it. Just say, yeah, I mean hypoxia, the first effects of, by the way 1862, some heroes decided to take a balloon up to 29,000 feet, right? And reported strange symptoms, including loss of vision, loss of hearing and paralysis of arms and somehow in all that they were like, get a balloon down, you know.

01:05:51

Okay. Tell tell the story. I was like 150 years ago, the first like experience of hypoxia. Yeah, so there's one thing to remember which is that you've got oxygen available to you, put your mask on and then deal with the rest after the rest after. Yeah, that's it. That's it.

01:06:11

Get all right. Yes. Bye.

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