Dan Snow's History Hit - Black Boxes: Recording Airplanes' Final Moments

Episode Date: July 18, 2023

They can survive in lava for half an hour and accelerations of 3,400 Gs. Their beacons can be detected 20,000 feet beneath the waves. Most shocking of all - they aren't actually black! (They're bright orange = the least common colour in nature.)Today it's the invention of the iconic Black Box (or Flight Recorder). We'll meet David Warren, the Australian who invented them. We'll learn how they work and try to fathom the strange fascination they hold.Edited by Tom Delargy, Produced by Freddy Chick, Senior Producer is Charlotte LongDiscover the past on History Hit with ad-free original podcasts and documentaries released weekly presented by world-renowned historians like Dan Snow, Suzannah Lipscomb, Lucy Worsley, Matt Lewis, Tristan Hughes and more.Get 50% off your first 3 months with code DANSNOW. Download the app or sign up here.If you want to get in touch with the podcast, you can email us at [e-mail], we'd love to hear from you!You can take part in our listener survey here.

In the midst of life we are in death, etc. Lorry drivers can plunge off cliffs, a logger can be crushed by a falling tree, a donkey ride can spell disaster. All of these deaths happened. None of them, however, were recorded. But if these people had been pilots, then those final moments, those moments of tragedy and disaster, would have been preserved

because they'd have been recorded. Recorded desperately trying to right the plane, rifling through the instructional manual, grappling with the controls, or flirting with the cabin crew, just as disaster was about to strike. Black boxes give us an insight into a moment where things that should never happen, things that we pray will never happen. Happen. Hello, welcome to Patented, a podcast about the history of invention from history hit with me, Dallas Campbell. Thank you very much for your company. It's lovely to have you here.

Last week, we covered the invention of the ejection seat and today I'm continuing the theme of health and safety gone mad. It's time for the iconic black box that lives silently listening in the cockpit of aeroplanes ready to record the fateful final moments. This is the story of how it came to be. So get ready to meet David Warren, an Australian who invented the first ever black box. We'll find out how that first one worked and why they aren't actually black or boxes anymore. And my guest today to talk about all of this stuff is Brendan Walker, aka The Thrill Engineer. Brendan began his career as an aeronautical engineer before veering away for a life in art, as well as rollercoaster engineering, TV presenting, and more.

And throughout his career, he's been fascinated by our fascination with black boxers and what they record. And he's created plays and installations exploring their story. So he is the perfect guest. It's the second time we've had him on the show. So if you enjoy this, then don't forget to listen to our episode about the history of roller coasters that Brendan did as well. It's terrific. Enjoy. There was a really amazing play. Well, it was sort of a play, I guess, a piece of theater. And it was called Charlie Victor Romeo. And I saw it in America years and years ago, like about maybe around about 99 or late 90s.

Charlie Victor Romeo stands for Cockpit Voice Recorder. And what they did was they had a kind of fake or a kind of mock-up cock. Well, I think maybe just like two chairs on stage. And then they played actual cockpit voice recordings of about a minute before. So you hear them sort of chatting. Everything's normal. They're talking about, oh, where they're staying in the hotel. And, oh, and this is nice.

And what did you do last weekend? And then it just goes quiet. And then on stage, there's this big screen where they kind of has the flight number and what happened. It tells you a little bit about the history. It was the most extraordinary, beautifully done bit of theatre.

Like really, you know, you might think it's macabre, but it wasn't at all. It was just really interesting. That sort of juxtaposition between absolute banality and then total panic sometimes, or just hearing how pilots react

to difficult situations. But then we get a bit more information and you didn't see that i'm guessing by the way you're looking and nodding you're kind of like you're like i didn't see that i didn't say it but i recognize all of the dramatic twists that you talk about there and i think it is so ripe for studying in a sort of theatrical sense or presenting because it is. And, you know, you're sort of being privileged to actually being part of people's very real lived emotions at that time. I think the recordings themselves, that is why they have such that sense of immediacy, even if you're just reading them as written word. They're also not just panic. It's not just people screaming and shouting.

It's very considered language. just panic. It's not just people screaming and shouting. It's very considered language. It's interesting just how the language changes and how suddenly when you're faced against something potentially catastrophic or actually catastrophic, how we behave as humans. And the black box recorder just gives you that extraordinary insight that, you know, anyway, it was interesting. It's worth pointing out at this point, just how vanishingly rare aircraft disasters are if you think about how many flights there are just go on sky scan or any of those things i mean the statistic i always have is at any one point there's a million people in the air which is a city's work which is crazy and there are never any accidents well very occasionally there are accidents of

course there are but i have another statistic which is you're more likely to die falling off a donkey on a beach than you are to die in an aviation disaster in your lifetime. Brendan, I've been saying it for a long time. We need donkey voice recorders on donkeys so when people fall off, we can capture that moment. For hilarity as well as obviously for forensics. Yes, of course, there needs to be some sort of public investigation into donkey beach accidents yeah hey listen thanks for coming on the show it's nice to see you as ever it's always good to see you i'm always happy you too let's not

delve into history quite yet how do they work what do they look like so we had held on in our hands i said at the beginning it's not black and it's not a box. So what does it look like? Well, they've gone through a bit of an evolution. But right now they are bright orange boxes. They're the size of, let's say, a couple of shoe boxes strapped together, that kind of size. They're metallic, but they're painted. And they'll have a few little plugs on the side for plugging in data cables, masses of data cables. So sort of like, I don't know, 80 pin socket on the side of it. And like the sort of little drawers

that you keep the pizzas in when you're on an easy jet flight, you know, they want to warm up your pizzas on the front. They're about that kind of size, you know. And what do they record? Is it just voice? There's microphones in the cockpit. And is it kind of like a magnetic tape on a loop? So it records a certain amount of time and then records over it. It doesn't record like the whole flight forever, does it? No, I mean, there are two components to the modern black box, which is the flight data recorder. So this is the data which is captured from all the control surfaces, you know, the rudders, the elevators, the trim, airspeed, altitude, all that stuff is being sampled. Well, now at a very high rate onto what we're currently using solid state recorders now to the moving onto microchips. But until fairly recently, everything was recorded onto a magnetic medium.

Still fairly recently, everything was recorded onto a magnetic medium. And it's the voice recorder, the cockpit voice recorder, CBR, which is the bit which we think about when we think of black box recordings. And they are, say until they moved on to solid state, they are recorded onto magnetic wire. Actually, just talking about recording flight data, I mean, the Rolls-Royce engines now, I mean, they are basically just producing data in real time all the time, and all the

data from those engines, how they're performing, gets beamed back to Derby, and it's unbelievable how much data an aircraft produces now. It's like just a data machine. Presumably, you could just have microphones in the cockpit that just beam back in real time. Yeah, but that would be awful.

I sat in, honestly, listen to bloody pilots banging on. My dad, for example. Is he a pilot? Yeah, he was a 747-400 captain for BA back in the day. And I used to fly with him, and it was always a kind of retreat because I would be in the jump seat in the days where you could fly in the jump seat before we went insane and locked the cockpit doors.

I didn't want to tell my dad that it was really boring because my dad would be talking about dad things to the first officer. So I used to go and just net back and sit in the back of the plane and drink martinis and watch movies. I thought you were going to say you just fiddled with the switches. I wonder what this one does. No, I certainly didn't fiddle with the switches. I knew my way around a 747 pretty well.

Okay, was it ever black? And was it ever a box? What is it made of? So a plane crashes, which is awful, obviously. We kind of route around over the wreckage and they find the black box. Oh, just fun fact. The reason why they're orange, obviously, it's a visual thing, so you can see them. But it's a very special orange called international orange. And it's the least occurring color in nature. There you go, fun fact. Let's go into the history I suppose. It must have been black. Why do we start calling it black box? Well let's start with why it originally was black box. So at the start of aviation clearly there were a lot of experimental aircraft and they wanted to be able to, well any new instrumentation

that was made, was made in aluminium. So I know you've sat in old cockpits of World War I, World War II planes, and everything was aluminium, and it was all painted black. It was what they did back then. So anything which was secret or experimental or even early radar equipment, they started to become known as black box technology, because everything sat in these little aluminium boxes, which were inserted into the aircraft. So this idea of sort of relating new technology and black boxes and aviation started to develop hand in hand with the evolution of aviation. And so there were flight recorders way back 1920s there was a pair of inventors in

finland before the second world war who were developing photographic techniques so basically they were running film and recording information from flight data so from control services as the light images on photographic film and clearly it wasn't designed to capture data if there was an accident, but for developmental reasons, collecting data was really important. When you say filming, were they filming the flight deck so you could kind of see the instruments? Yeah, so there was a mixture. Very early ones, they were...

Pilots waving their hands going, oh, crap. Yeah, so it was really just to capture the instrumental dating in real time. I think they became more refined in those methods. So essentially leaving marks on the photographic film, which is a little bit more like digital type recording. So there was this idea of recording data, very useful for analysing aircraft in development, but nothing really about recording information

at the moment of a disaster. And the idea also of recording voices onto different types of media was also being used during the Second World War for pilots, particularly, I think there's some early recordings from Lancaster bombers that they recorded conversations

as experiments on these aircraft. And again, it was just for historic documentation, I think really was why they were doing it. But the idea of putting those two things together, flight data recording and cockpit voice recording, this is what, well, I'm going to bring his name up. Yeah, let's have the inventor. Because presumably it must have been from a reaction of something, something happened it's like oh crikey we better invent a

thing yeah so post-second world war england have developed jet technology you know which obviously then we sold on to the us but you know we've now got the world of commercial aviation starting to blossom post-second world war and england and the empire the dwindling empire well i don't know the empire will never dwindle i'm joking before i'm gonna say it will if we have anything to do about it does post-second world war the commonwealth was incredibly important to the British economy. And the evolution of the de Havilland's Comet aircraft. Yes, that's right. It's coming back.

It was the Comet, the de Havilland Comet. First jet passenger plane, all kinds of issues. And they went, oh, crap. Yeah, so there were three of them. all kinds of issues and they went oh crap yeah so there were three of them famously seen 1953 and 1954 crashed in various locations around the commonwealth and after the third one they went right okay there's a pattern here like you know something's happening and it's you know the fact that there were so many experimental aircraft taking to the air post second world war so we're going got all this fantastic technology let's just use it for the good of humanity and do stuff with it and so

there was so many stuff literally taking off probably before we knew everything about it and so that's why there's quite a lot of disasters even i think donald campbell with his boats etc all this people pushing the boundaries constantly. So the comet crashes and there's a big commission set up, which is Commonwealth wide. And David Warren, who is working at the aeronautical research laboratories in Australia, is asked to join this commission because he was an expert in aviation fuel. So he had nothing at all to do with avionics. Maybe this new kind of jet fuel for high altitudes was an issue. And so he sat on the board, and that's where he started to get involved.

And he quickly realized, he's going, well, how high were they flying? What were they doing? People going, don't know. What speed did they get to? Don't know. And he was going, far too many questions. How is he supposed to operate? And this is where he started doing his own private research so tell me david warren who he david warren go right back

to his early days he loved chemistry he loved electronics i think his dad bought him a crystal radio set he was a ham amateur radio operator i dad, sadly, died in a plane crash when David was nine years old. Crikey. And is that the motivation? Well, presumably it must be the motivation. Well, I think it was because the aeroplane itself crashed into the sea and the debris sank.

And I think it was outside Melbourne. It was quite a big deal because his dad had just taken on a new missionary role. So he was quite a popular man, his father. So it was widely reported. So I think, I mean, that must, nine years old, that must stick with you for some time. I mean, crikey, there's an innovation story.

It's like your dad dies in a plane crash when you're nine and you're also a radio enthusiast and sound recordist. It's not a big leap to work out where you got that idea. But he actually pursued his passion for chemistry strangely i mean he went to i think it was the the woomerang rockets association or club he joined and then in australia yeah it is australia yeah room around yes and he then went to imperial college study aeronautical engineering where i went to study 40 years later i have to and then came back to work for the aeronautical engineering where i went to study 40 years later i have to like and

then came back to work for the aeronautical research laboratories developing aviation fuel because obviously after the second world war we got jet aircraft and the massive evolutions in the composition of aviation fuel i've just heard one of the listeners screaming down the um microphone saying to me it's not woomerang it's woomerah oh we thought it was woomerang because we thought of boomerang but it is australian this is where they did the rockets i just suddenly just as you were talking there i was like wait is it really woomerang no it's woomerang woomerang woomerang they won't mind i mean one of the funny stories today i saw his memoirs and one of the funny stories was just before he started working on The Black Box,

he was working for, I think, the Department of Agriculture, working out how much aviation fuel was required to create enough carbon monoxide to kill rabbits in their burrows. I know. It's this myxomatosis, rabbits in Australia. I think they were nibbling away at the crops. So he was kind of an inventive bloke and obviously turning his talent to all sorts of things.

I've actually got a little memorandum that he wrote. I might read it to you, see what you think. It says, this is from David Warren, Principle of the Suggested Device. So this is actually his first memorandum about the black box. He says, it may be assumed that in almost all incidents, the pilot received some pre-indication, either by sight, feel of the controls, automatic alarm, or instrument reading.

In most cases, this would evoke a complaint of difficulty or a shout of warning to attract the attention of the co-pilot. To preserve the valuable evidence offered by these few seconds conversation, it is suggested that the following simple device could be fitted to all major aircraft. A small magnetic recorder would be made in which a continuous closed circuit of steel wire passes an erasing head followed by a recording head in, say, a two-minute cycle. Such a device would provide a permanent memory of the conversation in the control cabin for the two minutes immediately prior to switching off, which would occur automatically in the case of an accident. There you go. Wow. Simples. Yeah, it's so concise,

yet absolutely contemporary. And I think some of the other things he mentioned in there, I think there was one idea that he had of ejecting the black box in the case of an accident so it doesn't end up in the disaster. I think after an aviation incident in 2014, thinking of actually instigating that, making that a requirement, civil aviation authority requirement, that they have this ejectable black box as well. So he had a massive amount of foresight, but able to write it so succinctly. Really good. And actually, there's another little paragraph here. He says,

careless control or error of judgment, as is often suspected to be the cause of landing and takeoff accidents, would probably elicit criticism, suggestion or warning from the co-pilot. So he's kind of thinking about, well, actually, this is the kind of legal aspect of accident investigation,

and this would also be useful. Yeah, and it's amazing that he's thinking about the dynamics of the people in the aircraft. It isn't just a machine he's interested in. He knows that people are critical to these stories. And for the real nerds, this is Mechanical Engineer Technical Memorandum number 142,

as opposed to 143 or 141. Which was obviously about the euthanization of rabbits. Exactly, yeah, exactly. I'm Matt Lewis. And I'm Dr. Eleanor Janaga. And in Gone Medieval, we get into the greatest mysteries. The gobsmacking details and latest groundbreaking research. From the greatest millennium in human history.

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by subscribing to Gone Medieval from History Hit, wherever you get your podcasts. He had seen, actually, the year before a wire voice recorder in a trade show made by a company called telefunken i know telefunken yeah so german are they well they must be good name isn't it tell it i remember seeing it on things telefunken it's beautiful he actually bought he bought one of these wire recorders and so he had that from the year before and he said well can't we get one of these on a plane and he was actually turned down so his first thought was let's get one of these on a plane

and start to record stuff and see what happens he was blocked by his boss he said no you work in aviation fuel you can't be doing classic kind of like innovation story so he went off and did it anyway people knew what he was doing but it wasn't really recorded in papers or minutes of meetings but he put one of these things on an aircraft in an aircraft cockpit there's so much noise there's lots of constantly so the sound of aviation electronics going on the sound of air so he started cleaning up the voice recordings he used a technique called band pass filtering so the voice range you know is a very specific frequency but the ability of audio medium to record stuff at very high frequency and very low frequency he thought i've got all this like bandwidth free I'm gonna maybe start sticking some information in

there so he found a way of using this wire recorder which was designed for voices to actually start putting some very simple information like the guys have been using photographic medium you know 20 years earlier to start inserting bits of flight data recording so So that really was, those first experiments were the very first black box recordings, I think, in their truest sense, when that moment of genius to bring those two elements together. What about that? I mean, as well as the kind of recording engineering, what about the idea that, okay, this is going to have to survive a plane crash. So when all the rest of the plane is obliterated, how do we make something that's going to survive? You see his first memorandum that he produced, and he starts to go through some very practical things, exactly those questions.

What is the force of an aviation crash? How much force do we need to withstand? There's obviously going to be fire. What if we can't find it? You know, the ideas of painting it a colour, putting streamers on it, putting a beacon on it so it could be found. So those ideas start to appear in this very first memo. And then also, say, the temperatures and also impact. So again, it's been through various iterations, but currently where we're at is there's commonly accepted that these boxes need to withstand a force of nearly 3,500 Gs. I mean, that's just phenomenal. Wait, okay, just, okay, 3,500 Gs.

So, for example, we are now experiencing 1G, sitting here doing a podcast. I went into one of those centrifuges once, you know, the astronaut centrifuges. I think I got to about like four and I started freaking out, which is nothing. You know, astronauts,

well, not just astronauts, you know, fast jet pilots train up to 9G, which is getting pretty hectic. And for the split seconds, you go above 9G, but 9G is kind of where you are. So 3,500 G,

that's going to be, that would hurt. Actually, it wouldn't hurt. You wouldn't feel it So 3,500 G, that's going to be, that would hurt. Actually, it wouldn't hurt. You wouldn't feel it. No, I think in that split second, I don't think, I mean, this is sort of maybe a little bit of solace. You know it's coming for quite some time, but when it happens, it's over before your mind is even able to comprehend.

But it is exactly that you're saying. It's not sustained for a long period of time. So actually, the aircraft would be in free fall for most of the time so the black box would almost and the people in there would be experiencing zero g as they're falling but then at that moment of impact it happens so quickly that is the sort of pancaking effect as this mass gets squashed into the ground so three and a half thousand g's so they've been looking into combinations of multi-layered structures, a little bit like, I suppose, those honeycomb structures, which are incredibly thin-walled,

but so strong, if you're actually pushing them in one particular direction, you know, if you turn them on the side, you can pinch them very easily with your fingers, but in one direction, you can stand on them. So the combination of materials and design of walls and then also the materials themselves you go from a very thin aluminium foil around the electronics then there's a core of dense material which must be you know i think there's ceramics in that material i can't quite remember its constituency but this is now to start making them heatproof as well so these things are now heat proof for i think it's about 30 minutes is the international standard now they have to be able

to withstand temperatures up to 2000 degrees fahrenheit that's the heat of lava basically you couldn't make an airplane out of this material that the old joke because it would be too heavy to fly and other problems one of the arguments early on was we can't afford to put this on an aircraft because weight is a premium and so there was a real fight and actually even to increase the length of time you might record requires extra tape and stuff so i seem to remember i may be misremembering this from my childhood as well my dad who i mentioned when he was based in manchester and he was on 111 out of manchester so this was early 80s i think before he was on the 400 he was on the runway and one of his engines blew up and everyone got off the plane totally

fine there was no casualties or anything like that and they used the voice recorder i think in the sort of post-mortem of the incident and it was kind of like my dad because he was a very good pilot was like this is how to be a pilot it was going to be used as a kind of this is exactly how it should be so we come on to particularly recording pilots voices the objections that unions like balpa who represents pilots there were lots of complaints and resistance from pilots that they might become culpable for mistakes that's interesting that yeah when security cameras kept coming along that idea of it raises questions doesn't it it's like well crikey do i have to watch what i say now i mean what if i make an inappropriate joke or i don't know like how's that all going

to work yeah exactly i think they were appeased by said actually it's only two minutes and it'll only be captured in an emergency and maybe it'll actually help yeah and probably it'll be on a flight that you died on so there'll be no actually that's no that's no comfort at all is it oh god held accountable i think some of the things that are captured which have been really interesting there was a flight in 1999 out of stansted airport it was a korean cargo plane one that i became really interested in because it's only up the road in epping forest from where i live so we start to get in i suppose evidence that particularly in that flight there were social dynamics that were at

play that led to the eventual disaster and in fact you know so these two pilots there was a pilot there was a co-pilot they both had military backgrounds and they were both from different social stratas in society and so there's a real air of deference from the co-pilot the co-pilot knew that there was something wrong so i think they've been reported one of the pressure tubes on the port side was blocked something like this and essentially the pilot was making very usual maneuver banking left but if you know to fly a plane which i've got some rudimentary ideas if you're banking left you also want to pull up as well otherwise you're going to start losing altitude and dipping down but he thought he was actually flying at the correct altitude the co-pilot was looking out the window going uh they were actually slipping literally slipping

out the sky but he left it too late before like essentially saying excuse me gosh yes i'm terribly sorry sir but that's interesting so actually the psychological component about human interaction between first officer, captain. A lot of the time they're going through the ABCs. Is it this? Is it this? Is it this? Then obviously, I mean, there was another set of flights around 2018, some 747 Maxes, which Boeing had installed some new software on them to do the trim automatic trimming to make sure that the aircraft were stable and level and the trim was basically making decisions for the pilots the pilots had no idea and they were making false assumptions about altitude and there was one

of the flights where the last moments of the recording are the pilots saying have you got the manual and they're looking through the pages reading through the manual is this recent is this the 737 max do you mean relatively sorry yeah sorry they are it's the 737 max and so sorry yeah yeah no no no yeah it was the uh the lion air crashes that was in indonesia on those aircraft I'm just looking here now, there was 189 passengers and crew died. So obviously a big deal. Yeah, it's a massive deal for Boeing, you know, a huge deal for Boeing.

I mean, it's really, you know, shaken Boeing. Grounding the aircraft, loss of confidence in the aircraft, wasn't just the flight data recorder. In fact, actually the flight data recorder, I believe on the first accident, everything looks normal because obviously the computer was reporting it was doing what it should do. It was only through the conversations that they managed to capture from the in-flight going, why didn't they know how to turn this thing off? What was going on? That this issue actually became revealed. So, you know, that mixture of sometimes you want to look at the data,

sometimes you really want to be looking at how the human in the loop is actually responding to what they're being presented with. Do you think, just as a sort of final thought, we talk a lot about driverless cars and things. I remember having conversations with my dad about, you know, not having pilots in aircraft, and I think everything automated. Is that ever going to happen, do you think? I mean, he was always like, absolutely not, for the obvious reasons.

But, you know, you wonder now with the advent of ai and everything else do we just take humans out of the loop altogether gosh it's becoming even when i was studying aeronautical engineering working in industry early 90s there was always this discussion about are we you know not discussion actually people developing pilotless aircraft the more you take them out the less trained they are and able to respond to data maybe it's a comfort thing maybe we like to know that ultimately our life is in the hands of another human but that's a scary thought too isn't it well it is when you think about driverless cars and you look at the statistics about

how rubbish the human brain is compared to modern computers. Well, I've got to say, I'm sure you've been in driverless cars. I've been in them and it's amazing how quickly you get used to it. Even though at first you go, wait, this is weird. But then after 10 minutes, you're like, who would ever drive a car again? Now, where things go wrong, obviously, that's the horror isn't it when things are going right it's a beautiful sort of relinquish of control and this idea of comfort and leisure but when things go wrong it's like you don't want to be in the hands of a cybernet and yeah terminator and that's a different podcast well i've noticed

actually on my podcast and regular listeners may have noticed as well, but the longer the conversation goes on, the quicker we get to talk about chat GPT at some point. That's the new rule. We have to end there. I know, exactly. We do. Yes. Well, maybe we need chatbots just to fill up the voice data recordings with aimless chit chat. There you go. Brendan, pleasure as ever. It's always a pleasure. I love chatting to you as ever. So thank you very much and come back on and we'll chat about something else yeah lovely really enjoyed it i mean i've got such a huge library of their disaster stories i'm now going to have to delve in and look at some of the specifics but it's a bit like looking through

the tv times you know it's like there are so many stories slightly bit more macabre oh yeah a bit more macabre everyone ends in a disaster yes it is everyone ends in a disaster anyway we'll see you soon brendan thank you cheers see you dallas bye so there we go black boxes thank you very much for listening if you enjoyed the show don't forget to go back and listen to our extensive back catalogue of interesting stories. We have wide ranging interests here on Patented, as do you. So don't forget to get stuck into those and tell your friends and family all about the series. Do the thing that the algorithms like, hit subscribe, hit like, and all those other bits and bobs that we have to do these days. And most importantly, if you've got a suggestion for a topic or a story you'd like us to cover,

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