Think about how much time and engineering went into this. But yet we can't have ejection seats to save everyone's life.

"Why don't they build the whole plane out of the black box?"

I could have sworn it was Jerry Seinfeld that said that, but apparently it was the great deadpan comedian Steven Wright.

Most places in America don't require seat belts for bus passengers either.

Including school busses.

Let’s see your design for 150 ejection seats per plane

is that all? I feel like any plane crash would be at 310mph at least

It could be done, it's a money issue.

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Doesn't commercial airlines fly at like 500mph?

Because that isn't realistic even in the slightest.

You can just say you have no idea how and leave it at that. If you had any idea how heavy and cumbersome and dangerous ejection seats were you’d understand what an impractical idea it is on a commercial liner

Thats easier to type out than engineer

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Everyones downvoting me, but I refuse to believe that a planet about to send people to mars, can't really figure out a way to keep planes from killing everyone in a crash. Of course I don't know how to do it, I also don't know how to build rockets to mars, but that doesn't mean someone out there isn't smart enough to do it.

That's what I'm saying, 310mph seems way too little.

I think they mean deceleration, as in plane crash

Sure that wasn't kilometers? Flights usually average 500 mph...either way still way above 310

The rest of the plane acts like a crumple zone, slowing down the recorder before it suddenly stops.

Well yes, but the plane is also a very handy crumple zone for the flight recorder.

“About to send people to mars” uhhh yea that’s not happening for a long time. We haven’t even been back to the moon since the 70’s. Just because the idea exists doesn’t make it worth investing in. The safety rate of planes makes the idea of 150+ ejection seats completely absurd. Do you realize how heavy these would be and you want them to have enough energy to stay in the air? Do you want to be able to afford airline flights? You’re missing very basic parts of why this would never take place.

Unless it blows up, then there isn't much to crumple...

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Parachutes for planes are becoming a thing, maybe that will be the next step.

Nobody's sending anyone to Mars. Quit listening to Elorn Mursk.

There was an idea to have fuselage ejection system

Acceleration is a vector; it has both magnitude AND direction. Deceleration is just a type of acceleration.

There is almost no chance the flight recorder comes to an instantaneous stop. The plane is going to crumble, so is the ground.

The ground is also going to crumble, even if it’s concrete

The whole top of the plane needs to eject first before the seats eject! It works in a fighter jet because the canopy which sits right above the pilot ejects in a snap then the pilot in a very short time. Seems impossible in a passenger plane. The weight and mechanics of it all in not practical.

ITT: Non-engineers.

What this spec is saying is not "survive a cruise speed to full stop crash in 6.5 ms" but rather it can survive a series of decelerations and accelerations (bouncing from one direction to another is technically an acceleration) since its very very unlikely the plane (in parts) won't bounce and roll and shed all that kinetic energy over a wide area. It's a logical and reasonable goal.

Granted, crashing full speed into a vertical granite cliff might exceed those specs, but that's an edge case and we'll put it in the training docs that doing so is ill-advised.

It's completely insane to engineer.

It's a suggestion that is so absurd it is difficult to know where to begin picking it apart. Anyone making it is either trolling or so incredibly ignorant you'd be wasting your time trying to discuss it with them.

Well, lucky for the rest of us some people out there dream up ways to do the impossible, like inventing airplanes in the first place. If everyone thought the way you do we would still be living in caves.

Fuck Elon, but it will happen

In a breakup it would hit the ground at terminal for the chunk it's a part of, which would be much less aerodynamic than the whole aircraft.

>but that's an edge case and we'll put it in the training docs that doing so is ill-advised.

OH YOU ENGINEERS!

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Not really. Most accidents happen near the ground, rather unsurprisingly, where the planes are going (relatively) slow because they intend to land or are only just starting to pick up speed to take off. Not to mention the speed limits set by law when operating near airports and at low altitudes.

That doesn't matter, it matters what the impact velocity of the record is, which will be reduced due to the plane crumpling.

...and there's assholes like me who say that we have the technology for cloud-based real-time flight recording.

Acceleration can be used for both, it isn't dependent on direction.

Now that I think about it, I took crap at 700 mph!

I wouldn’t be surprised if the flight recorder itself was surrounded by some impact-absorbing material, like an air bag or foam material.

Living in caves? Bro thinks just because something is way too cost inefficient and bad idea overall that we shouldn’t keep designing safety features. There are better methods. Even fighter pilots can be career endingly injured after one ejection from the immense G forces applied to the body ejecting from a jet. There have been parachutes deigned into the bodies of small aircraft like Cessna’s that will safely float a plane to the ground in the event of a catastrophic failure. At least this train of thought has a more realistic application than 150 explosive charged ejection seats ripping off the roof of a 747…

"In case you're falling make sure to not fall on the hardest rock"

It's not a money issue. Even a profit-driven aviation industry still cares about safety to some degree, because the public is deathly afraid of flying and any perception of danger leads to cancelled tickets and lost profits.

It just so happens that there are better ways to make a plane safer than to implement ejection seats, which (by the way) tend to break bones and ligaments in the spine. Maybe it would be better to prevent the need to eject from a plane in the first place.

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Airspeed might be 150 less if you were with the jet stream.

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No, we don't. Modern aircraft do have real-time data streams. Airlines and manufacturers can monitor onboard systems remotely. But the flight data recorders are in a different league. These systems need to work every time, worldwide, with zero downtime no matter the situation. It's absolutely imperative that the full data stream be captured, without interruption, in every circumstance. Your satellite connection might be lost if the aircraft is inverted crashing into mountainous terrain. The flight recorder might record moment-of-impact or impact+ data that would be lost if it needed to be transmitted. This is still the best we're able to do.

Yes, but cruising speed is also very far from anything to crash into.

At a closing speed of 1,000 mph, a head on collision wouldn't leave much on the recorder anyway- you wouldn't have time to speak between perceiving the oncoming and impact.

Plane just disintegrates? Engines gone so thrust lost, what's left falls by gravity against wind resistance, so what is terminal velocity for a powerless fuselage?

Otherwise, most crashes will be at lower speeds, as the pilot tries to soften the impact with whatever slow-down ability is left.

Yes I believe it if it was with a tailwind. The air around them was moving 150-200mph so the plane relative to the air was below 500mph, not breaking any sound barrier.

In theory, most pilots won't crash their planes at full speed.

In practice, almost every crash happens close to take off or landing, and the plane is flying slower than cruise speed. A lot of crashes come from stalling the plane, which also lowers the speed of the eventual lithobraking manoeuvre.

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uninformed asshole* ftfy.

This. I love watching and reading about air crash investigations and this is one of the things that they like to stress: most of the accidents happen shortly after takeoff or just before landing. This includes both fatal and non-fatal accidents. The kinds of accidents that happen when a plane suddenly falls from the sky while at cruising altitude are pretty rare.

Well, even with those, the impacts are still when aircraft is landing :D

TIL who the real edge lords are.

I forget the setup, but there's a joke involving a physicist and how the gas pedal, brake pedal, and steering wheel are all accelerators.

Laughs in ADSB-out. No it's not as accurate as the FDR.

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>cruising at a cool 700mph

likely due to the jetstream effect throwing off the numbers.

you were probably in the polar jet which can reach speeds of up to 275 mph and runs west to east so if you were going TO EU, the effect of this tailwind could have easily boosted your speed 'across the ground' (which is what the SATNAV systems report) to 700 mph without any sound barrier shenanigans but 'airspeed' relative to the surrounding air was probably 500-550 which is standard cruise these days to conserve fuel.

They're not installing 150 ejection seats in airliners because they think it's impossible, they're doing it because they know it's a shit idea. Same reason why they don't have parachutes under every seat. What the hell do you think would happen if an untrained and unprotected civilian was blown out of a pressurized cabin at high speeds and high altitude? This is real life, not an episode of Wile E. Coyote & The Road Runner lmao.

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Now if only you’d manage to do the impossible and stop talking when you have nothing intelligent to say.

Interesting how simple a black box's design really is. Plus underneath their protective shell many still use old magnetic tapes for recording data.

I haven't heard the joke, but yes, that would generally be true.

> The speed of sound is around 660mph

true but the jetstream going US to EU is doing a lot of that lifting to get a 700mph readout on the SATNAV system..

700 mph 'across the ground' can also and at the same time be 550mph 'airspeed' when you surf the polar vortex going west to east.

Even though the aircraft is moving at 700mph across the ground, there is no sonic boom or breaking of the sound barrier which requires the aircraft to break 660mph in airspeed.

The polar jetstream tailwind is no joke. It's how/why the typical NY to London flight time is approx 7 hours and London - NY is 8 hours +

They take advantage on it going to London and try to avoid it as much as possible when going back to NY.

Deceleration is acceleration in a negative direction.

Why stop at 3400 geez?

I studied aircraft accident investigation in college. Fun fact, you can tell if a fire occurred on post crash or in mid air by analyzing which metals have melted and cross referencing their melting points to fire temperatures. Fires burn much hotter in air because the constant flow of oxygen.

Another fun fact. In prop airplanes you can tell if the engines were running at high speed vs if they running on low power based off the way the props are bent. If they are bent forwards then they were running at high speed at the time of impact and if they are bent backwards towards the aircraft then they were running at low speed.

Black Box Down is the podcast for you.

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Aerospace engineer here: something this doesn’t mention is frequency bands. I’ve had parts that require 200g in low bands (basically just the thing moving) and 20000g in high bands.

Flight recorders are usually near the empennage which often remain intact after crashes, it's the area that suffers the least damage in most cases. Some FDR are even designed to be ejected before crash.

If engineers are so smart why don't they design the whole plane to these specs.

Thought so.

I mean, maybe eventually, but no one is about to go to Mars any time soon.

The orange box isnt, its just mounted in the plane. If there was one, I havent seen it. Internally it could be somewhat cushioned.

It’s not it’s typically installed in the tail. The only part that’s typically hardened is the storage, the electrical interface is designed to be changed out. In the pictures fdr the orange cylinder is mass storage which the transponder is attached the silver cylinder. The rest of it is trash in a crash.

I would like to make a cryptic statement. Please think about it. Then You can comment and call me stupid, again. Here we go:

"I hope they have Electronic Skip Protection on the recorders."

27 years ago...

I'll go on...

See, minimally, I would see a data splitter. (Or an output from the recorder.) Goes to the best available satellite technology. Unlike transponder, it cannot be turned off. Arguments both ways on that one. Bottom line is, sure, keep that hardware, just give the satellite link a data feed.

In the event of a crash, the data would be there in the satellite system. Maybe, what, 80-90 percent of the time with good satellite coverage. That, to me, is a bit of a benefit. Instead of waiting for a search, that has a finite probability of failing, for the data and voice recorders, there is a good chance the data will be available at the push of a button.

Could have been really valuable for Malaysian Air Flight 370. (2014)

That’s a lot of data being collected and stored for an event that’s never supposed to happen. Should aircraft like VH-OJU store data for every single cockpit conversation and every single thing that happens during the flight for 23+ years, only to be retired after a long career with zero fatalities? Such a waste of resources particularly in a time when satellites are becoming increasingly crowded.

The Bijlmerramp (plane crashed in a flat building) crash happened in a populated area and the recorder has never been found. I always wondered what happened to it.

Not really. Cirrus’ CAPS system has saved a few aircraft but it has largely not been accepted by the aviation industry. It’s also a light 4-seat aircraft rather than, you know, a 180-seat jetliner.

We do. They're called tanks.

You’re ignoring any connection issues: if the aircraft cannot transmit the data to a satellite for whatever reason, such as it’s actively crashing, then it doesn’t matter how you are handling the data once it’s at the satellite. Even if you have 90% of coverage during normal operations, when planes start failing and the data is most critical the successful connection rate is going to plummet.

This is especially true once you start recognizing the types of crashes. The types of crashes where you are most likely to have connection all the way to the ground generally have few or no fatalities and the aircraft is recovered largely intact, such as the Miracle on the Hudson. In these cases you easily recover the flight recorder and can compare the data to survivor interviews and the recovered wreckage.

The crashes where you want a satellite connection are those where you cannot recover the flight recorder or the extremely rare cases where it is unreadable. These crashes almost by definition have no survivors and no significant debris recovered. For the crashes where you have to heavily rely on FDR data, the aircraft almost always becomes uncontrollable and any high-gain antenna necessary to transmit the dozens to hundreds of data channels (and many are reaching 1,000) would lose connection with a satellite network. When you need the data most, you don’t have it.

About the only time this would have been useful is MH 370. In this case, however, you don’t need to send all of the flight recorder data to a satellite network, just accurate position data at regular intervals. The problem with MH 370 is the search area was so fast we couldn’t find the recorders before their pinger batteries died, but with position data you would drastically narrow the search area and find the recorders and more importantly wreckage quickly. At that point you can use a low-gain omnidirectional antenna, much more likely to function in case of major maneuvers, and even if you lose that data the search area has shrunk dramatically.

>Should aircraft like VH-OJU store data for every single cockpit conversation and every single thing that happens during the flight for 23+ years, only to be retired after a long career with zero fatalities?

You dont have to keep the data for all time.

Serious answer: the plane might survive, but its interior is going to look like the aftermath of that scene from Event Horizon.

I believe that the flight data and voice recorders loop after a set time, perhaps 30 minutes.

The proposed system would also only store for 30 minutes, unless there was a loss of signal. Resumption of signal, would send buffered plane data, and reset the timer.

If they were at full speed sure, but when planes are engineless (most planes crash when they have no thrust at all), I suspect the speed they touch the ground is very slow as they just lose lift entirely due to lack of speed.

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Nice

Why?

I am pretty sure that was never proven. Although i know Israël never gave full disclosure on what cargo was on the plane.

I actually have worked on these. The one pictured is an HFR-5

Several things. You assume that as a plane is crashing, the datastream fails. Why? Given such, any data are better than none.

Last point regarding rarity of use: How often do flight data recorders get read? RARE instances.

The title of this thread marvelled at the technology of the hardware devices. I'm sure a fraction of that technology could make online flight recorders happen.

> Some FDR are even designed to be ejected before crash.

I never heard this before--is a parachute system used post-ejection?

They should make airplanes withstand an acceleration of 3400 g for 6.5 milliseconds

The aircraft I'm working on isn't an automatic system. It's manually by the Pilot.

It's a large foil that simply fly off and design to float and protect it's content if it lands on ground. It's not parachute but it's very light and large so it doesn't fall down like a rock.

Most airplane crashes are out of spec landings.

Not a lot ..

"Did you just hear a giant fart?" "No, that was just a sonic boom--we're doing 700mph!"

Yep. A plane built to those specs would not leave the ground.

> It's manually by the Pilot.

"Hey co-pilot, grab the 'Gonna Crash' checklist. What's it's say for Number 1?" "It says 'eject Flight Data Recorder' ". "Check".

Same thing happens when you aren't in a plane.

Some of the passengers will probably absorb the energy as well.

Weird brag for someone who designs astronaut sex toys.

Typically interior stuff is rated for twice the Gs as the rest of the aircraft, so for civilian stuff that would be 18G ultimate.

Lol. Informative and cheeky. Oh…. You.

Flight Control loop:

>if(maneuver.WillCrash()) {
>
>maneuver.Don't();
>
>}

My first thought as well. They've certainly got a lot more to worry about/ do if they're ever in a situation where they might need that.

Given the ability to be in constant contact with satellites and whatnot, can’t we just have the black box data uploaded in real time and do away with the search for the box after a crash? Are there so many flights that there wouldn’t be enough bandwidth?

9/11 has entered the chat

What happens if your data uplink gets damaged? Black Box data is only useful when things go wrong.

What good would it be as a data recorder if it's ejected before the crash

It floats, the broken aircraft don't.

If the Malaysia airline crash 370 was equipped with one of these we would have it recovered.

Couldn’t we do both? Have the uplink and, if it’s disrupted, then go to the box?

Ah, thanks for describing it in knots for me. Definitely puts it into perspective. 🙄😂

Is there a reason why flight data can’t be transmitted wirelessly, with a satellite link perhaps?

Fairly sure we do. There's at least some info that gets sent to the ground in realtime.

NTSB showing the press how they work, take one apart and show how they get the data organized in the computer if anyone is interested.

It’s interesting how they talk about how data is spread across the memory chips on the board and how losing some doesn’t mean the data is gone, just reduced fidelity.

https://youtu.be/mWLBPtLu_JY

Still haven't found that plane.

Unless you were over Lockerbie.

So, can engineers not build a better one? So many stories I read have been about the difficulty and inability to locate the boxes. Why haven't you and you engineer buds made a better one?

I think they meant "what value is it if it doesn't record the actual crash data and is ejected too soon to gather any meaningful evidence?"

I could be wrong though but i think that was their intent.

Should make the whole plane out of that

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A Boeing cruises at 500mph so yeah, don't know why such a low spec

Imagine the chaos of 180 panicking people trying to evacuate with parachutes. You would get people opening their parachute in the plane, just as they are leaving the plane, not waiting until they are clear of the plane.

Mentor pilot did a video on that, iirc it's just too much data + ridiculous rarity of the accidents, these factors make uploading too impractical

For the non-European Americans - 10 knots = 9 meters which is roughly 18 feet (the height of 3 six-foot tall men).

Well, it would be safer ...

not if you are russian.

Why don’t they make the entire airplane out of that material… problem solved!

We're givin' it all she's got Cap'n! We canna break tha laws o' physics!

The industry is working on it, but it's difficult to get the industry up to speed quickly due to cost/infrastructure issues and, as with most things, pandemic delays.

ICAO GADSS.

EASA (European aircraft) have adopted Jan 1 2025 to mandate that all new built aircraft exceeding 27000kg have such a system installed. Offhand I don't know if, ever, existing older aircraft or smaller ones will need to install as it's a very expensive modification to integrate into an aircraft.

I'm also not aware of any current implementation timeline for FAA, Canadian or other country registered planes. I think India has adopted the ICAO mandate, which has the same 2025 date. I'm much too lazy to try to investigate this in-depth.

You’re pretty much liquified at 3400g.

ICAO GADSS recommendation. A certain part of this idea is being implemented but it's very costly and will take time. Of the big nations, EASA is taking the lead, with a new aircraft of 27000kg+ mandate to have these systems installed by Jan 1, 2025.

To my knowledge existing aircraft won't be retrofit, but I could be mistaken. At least, not any time soon.

The industry is constantly studying and recommending new regulations and standards, it's just always a balance of feasibility, cost and the incremental safety increase.

3400g is equivalent to 3400g where g is the acceleration due to gravity, g = 32.174 ft/(sec^2). 3400g's is an acceleration. By assuming the entirety of the impact is 0.0065seconds, and assuming the final velocity (V_f=0mph), we can solve the initial velocity (V_i) algebraically with the kinematic relation: at=V_i-V_f

This can be rewritten as: a*t=V_i V_i=(3400 * 32.174fpss)*0.0065s= 707.2 feet per second

there are 22fps/15mph, so

V_i = 707.2fps * 15mph / 22fps = 484.8mph

I got an impact velocity of 485mph and I'm not sure how I got it wrong.

Then get to work designing and certifying it.

In the meantime, the next generation of aircraft tracking and distress alerting is GADSS, and more than a few smart people have been working on it. It'll start to be implemented in some countries in 2025.

Feel free to go to the source material at ICAO, read the EASA rulemaking and means of compliance guidance and tell the industry that you're "sure" they could do better.

I'm not wrong, it must be more to it than the basic kinematic equations cover. Even calculations using distance instead of time yield an impact speed of 390mph.

That’s actually a lot lower than I would have expected. Brb, going to see what the permits are like to crash an airplane.

Maybe a little more than I’ll-advised. I’d say that you should probably bold those words, make sure they understand how I’ll-advised.

Those bastards think Pi is 3, and g=10.

Engineers are all sick in the head, I tell you.

I think he was referring to the sensitive meat bags enclosed in the plane.

That is actually required per the current standards.

You have both a relatively low telemetry rate that is transmitted via either satellite radio or ground radio, and a higher rate data stream that is recorded locally

Your assumption is that the acceleration is constant over that time.

Typically. Specifications like this would be in a half sine wave of acceleration. Although other acceleration profiles are possible

That is no longer true. Modern ones use solid state drives

> Granted, crashing full speed into a vertical granite cliff might exceed those specs, but that's an edge case and we'll put it in the training docs that doing so is ill-advised.

We should setup a remote control passenger plane filled with crash test dummies to test this, to see if it does exceed the limits of the black box.

That can be solved up until a certain point by submerging everyone in liquid and forcing them to breath liquid oxygen. We'll also have to inject liquid into their body cavities as well.

https://space.stackexchange.com/questions/5635/max-g-survivable-suspended-in-water

Thanks Meyer, that makes sense. A half sine wave averages about 0.63 of peak acceleration and 485mph x 0.63 gives right at 310mph. I'm open to literature on this if you have any recommendations

Probably goes a bit faster than that when nosediving into the ground

Mll standard 810 goes into a bit of detail on shock testing,. Although it is not specific to black boxes.

I worked in the ordnance industry. We had to design warheads and electronics that could withstand 60,000g's for 20 milliseconds. These were used in "hard target warheads". Ones that had to penetrate a reinforced concrete bunker and still function properly. You can engineer things to with stand virtually anything. The physicist Lew Allen, in the 1950's experimented with getting steel balls to survive within the nuclear fire ball of an A- bomb blast.

Because we're trying to make a plane, not a train.

Investigators aren't interested in impact data. They are interested in the causes of the plane leaving normal flight. Yes, impact data might be useful but that's not what the recorder is for.

So let's say the recorder is ejected a minute into the plane leaving normal flight...and the flight continues for another several minutes. Isn't that info highly relevant and sought after? Or are you talking seconds before impact that it's ejected? I'm curious how that mechanism works...certainly not a manual process by a terrified flight crew.

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The memory storage is surrounded by foam, but its main purpose is as heat insulation if there is a fire.

Hey look at mister fancy pants over here flying Japanese Wagyu steaks

I'm not familiar with the actual ejection systems. But what you want a FDR to capture is attitude/altitude/speed etc and systems information. So when you have some kind of catastrophic incident you can identify the failures that led up to it. Were I designing that system it would be completely automated as no flight crew is going to even be considering FDR, nor should they. Also possible that it's structurally designed to separate on impact. For example, it stays in the plane until the moment of the crash, but the force of the crash compromises the installation of the box to separate it from the aircraft. Kind of like the intentional version of high speed car crashes with unbuckled passengers that get thrown clear during the crash sequence.

Why can’t we call them Orange Boxes?

Not as a large piece but a lot of smaller pieces have washed up on various shores around the Indian Ocean.

Was the Lufthansa crash over 600mph straight into a mountain? Or the China one that was nearly vertical?