You must log in or register to comment.

EndlessEmergency t1_itqwagn wrote

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.


somegridplayer t1_itqxqwl wrote

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



tryingtodefendhim t1_itr5bmu wrote

TIL who the real edge lords are.


[deleted] t1_its3r6o wrote



Sharp_Building3453 t1_itty2e0 wrote

But if you came to a full stop in the jet stream then your air speed would then be negative, so the resulting math is the same.


LiamtheV t1_itt29xc wrote

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

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


_Weyland_ t1_itr0bdt wrote

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


obscureferences t1_itrr73k wrote

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

Thought so.


shingofan t1_its0sz2 wrote

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


SFXBTPD t1_itsc6p9 wrote

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


crowley7234 t1_itt2ym0 wrote

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


TheSleepingNinja t1_ittdcsp wrote

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


Akanan t1_itrlmmk wrote

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.


falconcountry t1_itsfn39 wrote

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


Akanan t1_itsfu0d wrote

It floats, the broken aircraft don't.

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


Odeeum t1_itsnw0e wrote

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.


Cerebro64 t1_ittb7u3 wrote

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.


Odeeum t1_ittbnny wrote

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.


Cerebro64 t1_ittdmlc wrote

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.


dressageishard t1_itsk7xq wrote

Still haven't found that plane.


flakAttack510 t1_ittknpx wrote

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


guitarnoir t1_its78x8 wrote

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

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


Akanan t1_its7l69 wrote

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.


guitarnoir t1_itsaefq wrote

> 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".


Realistic-Astronaut7 t1_itse52i wrote

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.


Pfheonix t1_itsd3p8 wrote

Flight Control loop:

>if(maneuver.WillCrash()) {


tminus7700 t1_itt7m63 wrote

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.


doglaughington t1_itsm0b6 wrote

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?


mtled t1_itssrej wrote

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.


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.


Henri_Dupont t1_itssq8z wrote

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


SpaceBoJangles t1_itswjcc wrote

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.


EmbarrassedHelp t1_itt4c1x wrote

> 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.


LesWhite t1_ittperb wrote

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


MuForceShoelace t1_itqqcqg wrote

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


incapable1337 t1_itquub0 wrote

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


Brandon432 t1_itqvu39 wrote

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


rigorousthinker t1_itqzh9z wrote

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


KTKloss t1_itrvcd6 wrote

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


Fakenamefreddy t1_itrw4pi wrote

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.


getmybehindsatan t1_ittdcbh wrote

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


jimflaigle t1_itsbqmx wrote

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


Citysurvivor t1_itqy8w3 wrote

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.


surgingchaos t1_itr3733 wrote

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.


southernwx t1_itr4ekf wrote

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


threwzsa t1_itrh078 wrote

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.


kaotate t1_itrin2e wrote

Black Box Down is the podcast for you.


theorange1990 t1_itqy9lp wrote

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


zJordan t1_its28ae wrote

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.


The_Krackening t1_itrky01 wrote

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.


jimflaigle t1_itsbwv1 wrote

Weird brag for someone who designs astronaut sex toys.


OldMork t1_itu1qch wrote

the hose they pee in got several different use...


wmantly t1_itqst46 wrote

Doesn't commercial airlines fly at like 500mph?


Jonathan924 t1_itquttq wrote

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


wmantly t1_itquzxc wrote

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


runtscrape t1_itqxhqt wrote

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.


[deleted] t1_itqttw7 wrote



way2funni t1_itr9i0c wrote

>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.


small_giant t1_itqz8s9 wrote

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


guitarnoir t1_its7xjb wrote

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


48for8 t1_itqujzz wrote

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


[deleted] t1_itqv0w2 wrote



Poop_Tube t1_itr2052 wrote

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.


friedmators t1_itr0wcs wrote

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


[deleted] t1_itr0t97 wrote



way2funni t1_itrd1bi wrote

> 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.


wmantly t1_itqtze0 wrote

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


Brandon432 t1_itqvsci wrote

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


Ishidan01 t1_itr1z7o wrote

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.


popsickle_in_one t1_itr2h7w wrote

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.


LNL_HUTZ t1_itse8vt wrote

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?


ulyssessword t1_itsfhlr wrote

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


LNL_HUTZ t1_itsfu5s wrote

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


ulyssessword t1_itshv8e wrote

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


Star_king12 t1_itsqi3h wrote

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


mtled t1_itstmeo wrote

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.


meyerpw t1_itt3rpm wrote

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


casualphilosopher1 t1_itrcebj wrote

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


meyerpw t1_itt45pm wrote

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


MASTER-FOOO1 t1_itttpay wrote

not all, air bus of emirates airline is still using the tapes and won't switch until 2028

Source: I'm an engineer who was maintaining and installing them before covid hit.


Googlemapsflow t1_itstq0e wrote

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.


Googlemapsflow t1_itsv4vg wrote

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.


meyerpw t1_itt449u wrote

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


Googlemapsflow t1_itt4wor wrote

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


meyerpw t1_itt6bin wrote

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


BasedOnAir t1_itzeyij wrote

You didn’t get it wrong. OP didn’t mention that the spec says it must withstand 310mph to 0mph over a distance of 18 inches. Not instant-stop over zero distance.

The wiki explains this


Googlemapsflow t1_itznpjt wrote

to stop over a time period of 6.5msec implies that it stops over a distance. I calculated velocity over the given 1.5ft distance and it was a different impact speed. The real answer is that they reported a max velocity when speed calcs are performed assuming a half sine wave impulse. Meyer explained it to me in a different comment


Sufferment t1_itrdq95 wrote

Why stop at 3400 geez?


ChappaQuitIt t1_itte51z wrote

Why can’t we call them Orange Boxes?


pewpewpewouch t1_itrytd0 wrote

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.


[deleted] t1_its2fn2 wrote



pewpewpewouch t1_its4z06 wrote

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


ChifforobeDestroyer t1_its5iq1 wrote

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


NerdyJerdy20 t1_itsfvkp wrote

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


shinobi7 t1_itsh3w9 wrote

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


colin8651 t1_itshzk9 wrote

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.


jmdunkle t1_itspaj2 wrote

Should make the whole plane out of that


Double_Distribution8 t1_itsruma wrote

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


djr41463 t1_itssl5b wrote

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


Ishidan01 t1_itt9k51 wrote

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


TheDeadlySquid t1_itstfli wrote

You’re pretty much liquified at 3400g.


StuartBaker159 t1_itsvh0e wrote

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


SirLoinThatSaysNi t1_itu4z4q wrote

I suspect it's because they are inside the aircraft so have several layers of crumple zone around them. It is not, generally anyway, just the exposed box hitting an immovable object.


EdofBorg t1_itu7zfe wrote

They should be made from the same material as Saudi Passports which survived the crash, fire, and secondary explosions in Towers 1 and 2 while the flight recorders didnt.


Admetus t1_itu84rv wrote

This is a nice question of impulse and Newton's second law for physics class. Though pretty macabre...


Milnoc t1_itusey3 wrote

It's amazing just how much punishment these things can take. Look at Air France's Flight 447. Not only did the recorders survive the initial crash, they also survived being at the bottom of the ocean for years! And in spite of all this, the data was fully recovered and explained exactly why the flight crew failed miserably at their jobs.


HappyHighwayman t1_its7djv wrote

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


Romando1 t1_itsedi4 wrote

9/11 has entered the chat


Prolapseinjudgement t1_itqufzb wrote

I think they mean deceleration, as in plane crash


Brandon432 t1_itqvm67 wrote

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


zaahc t1_itr6ajz wrote

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.


Brandon432 t1_itrcz94 wrote

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


theorange1990 t1_itqz1s9 wrote

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


NetDork t1_itrd3qi wrote

Deceleration is acceleration in a negative direction.


Bott t1_itqypgw wrote

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


zaahc t1_itr1yke wrote

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.


Bott t1_itrwr0x wrote

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)


747ER t1_itrypjl wrote

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.


Halvus_I t1_its0qyl wrote

>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.


Bott t1_its0vbd wrote

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.


beachedwhale1945 t1_its0f4l wrote

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.


Bott t1_its742q wrote

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.


mtled t1_itsuf8i wrote

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.


beachedwhale1945 t1_itvr7oy wrote

>You assume that as a plane is crashing, the datastream fails. Why?

  1. Connection issues are common problems for normal operations and should be expected for any such system.

  2. To communicate the volume of data an FDR captures with satellites you need a high-gain antenna with significant power requirements. To reduce said power requirements a directional antenna is best, such as for Starlink. These will naturally loose connection if a plane is no longer pointed up, such as diving towards the ground and especially diving while inverted. This isn’t GPS where the data transmitted is minimal, there is a massive amount of data in an FDR.

> Given such, any data are better than none.

And the cases of no data are practically unheard of. If you can get to the wreck, you can get to the flight data recorders.

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

Every single time they are recovered, with dozens per year as legal requirements push them to smaller aircraft with lower safer standards compared to airlines. You may not read an FDR in case of a bird strike where the aircraft lands safely, but even then removing them is common.

Name another crash in the last decade besides MH 370 where the black boxes were not recovered.

>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.

It is far easier to make anything wired function reliably at high bit rates compared to something wireless. Landlines came a century before wireless phones (satellite or cellular). Wired Internet long predates wireless, and most of the global internet passes along undersea cables rather than satellites. A couple months ago T Mobile and SpaceX announced they were going to used Starlink satellites to end dead zones: these require large version 2 satellites too large to fit on a Falcon 9 and will initially only offer text message support rather than real-time voice calls.

You’re asking for something far more ambitious: real-time communication with thousands of airliners in the air every second with high data output from each. Thus would require massive allocation of radio frequencies (which are already limited) and require thousands of new satellites to function (with cheap launches at about $1 million per satellite using Starlink as an approximation, which is far cheaper than most). All to solve a problem that is so rare it has only been an issue for a handful of crashes over the past several decades (we haven’t even discussed how most crashes are within a few miles of an airport).

This could be solved far more easily by a far simpler solution: every five minutes in the air the aircraft transmits its current GPS coordinates. If it goes down, the search area is now small enough that you can easily find the black boxes.

Your naïvety on such problems shows how little you actually know about the subject and engineering in general. A complicated solution for a niche problem almost never sees the light of day.


lol-117 t1_itr6gen wrote

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


waffles-n-gravy t1_itqovt5 wrote

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


AnthillOmbudsman t1_itqp5h2 wrote

"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.


happydgaf t1_itqqb8n wrote

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


waffles-n-gravy t1_itqqu2l wrote

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


happydgaf t1_itqt9up wrote

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


waffles-n-gravy t1_itqtyjy wrote

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.


happydgaf t1_itquvbg wrote

“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.


waffles-n-gravy t1_itqwkt3 wrote

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.


happydgaf t1_itr04ae wrote

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…


Skulldetta t1_itr9o8l wrote

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.


OneBlueHopeUTFT t1_itrc0nz wrote

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


kingzilch t1_itqv98a wrote

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


waffles-n-gravy t1_itqwnyo wrote

Fuck Elon, but it will happen


kingzilch t1_itrsw0z wrote

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


Citysurvivor t1_itr0q9n wrote

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.


THenrich t1_itqw711 wrote

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.


ItDoesntMatter59 t1_itqtjnw wrote

Thats easier to type out than engineer


jimicus t1_itqwc7a wrote

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.


brighter_hell t1_itqv73o wrote

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


747ER t1_itrz7c4 wrote

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.


Twuggy t1_itsq6og wrote

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.