[bnycum]

I work on flight data recorders, mainly in rotorcraft but some small fixed wing aircraft. The current generation does use a satellite connection for real time tracking, as well as sending high level caution information, and a few data parameters. Really the cost of sending data over the satellite is the real issue. However this is coming down.

Outside of that, the ADS-B requirement is a huge help in knowing where aircraft are and where they are going.

[ajsnigrutin]

Is there some good explanation, show a sinking titanic was heard both in london and new york, but a modern(...ish) MH-370 can just dissapear?

I'm sure that there are a bunch of factors in play, but tracking a plane seems like a relatively simple and a high priority thing to do, and relatively cheap compared to a total cost of a plane. GPS, satellite connectivity, battery backup and even in a case of a total explosion, at least you know the last location, speed and direction to try to find the wreckage.

[ipython]

The difference is that the mh370 pilot deliberately took actions to avoid tracking. At some point if you can’t trust the captain of your vessel, that person can disrupt or disable most any system put in place.

If the captain of the titanic intended on sinking the ship without a trace, he most certainly would have succeeded as well.

A more apt comparison would be AF447, which took a few days before the wreckage was found. https://en.m.wikipedia.org/wiki/Air_France_Flight_447

[ozr]

Physical access can generally circumvent any security precautions, but it seems like there are some fairly simple schemes that would work well to prevent a disturbed captain.

E.g.: disabling the tracking system could require accessing a section of the plane inaccessible while it's in flight. Combine that with a hardware interlock system that would prevent the plane from taking off when it's disabled, and that should be sufficient in the vast majority of cases to prevent 'lost' planes.

Is there ever a valid reason to disable the recorder/tracking systems in flight?

[SoftTalker]

Captain needs to be able to pull a circuit breaker for virtually anything, in case of electrical fault, fire, misbehavior, needing to hard-reset some bit of avionics, etc.

Commercial passenger aircraft have redundant systems and you can disable almost anything as needed and still fly (up to a point of course) in case of emergency.

[ozr]

I can understand needing to have that option for most things, but a blackbox flight recorder ought to, by it's basic design, be read-only and have little to no dependencies with the rest of the aircraft. E.g.: a failed APU should not disable the blackbox, since you want to be able to record that the APU failed.

[samtho]

First off, there are two recorders: the cockpit voice recorder and the flight data recorded.

The voice recorder needs power which is provide by the aircraft and is a rolling 2-hour recording. If there is an incident, the captain will pull the breaker to this system to prevent the recording from being overwritten after on the ground, or, in the worst case, aircraft destruction will cause the severance of power to the device for a similar effect.

The flight data recorder a very dependent on all the systems of the aircraft, it listens on all electrical buses, senses the position of controls, and records datapoints at a defined rate for a rolling two hours of flight time. It has a small battery system to capture what it can, but if you lose engine generation and your APU, you either gliding to a crash landing in the best case or you are just hosed and it will be literally seconds before you’ve reached the ground.

Both of these things are not read only, they continually rewrite their memory because it’s usually the last bit of flight data that matters. There are pushes to make a system that can allow for 18-20 hours of flight data, but everything moves slowly in avionics.

[SoftTalker]

Yeah I'm sort of speculating and agree for the most part but obviously the data recorder is communicating with every other system on the aircraft for which it records data. If the data recorder had some kind of fault that was creating interference with these systems, maybe there's a scenario where you have to be able to shut it down.

If I'm thousands of feet above the ground and the system keeping me in the air has some kind of fault, when I say "Hal, shut down that faulty system" I don't wan't the answer to be "I'm sorry Dave, I cannot do that."

[refurb]

Electrical wiring fault starts a fire. Not sure we don’t want a pilot to be able to pull circuit breakers for everything on board.

[antonjs]

You could always have some breakers that could only be pulled by the chief flight attendant, or at least signal to someone in the cabin they were being pulled.

[bornfreddy]

Captain should be able to disable the transmission, but if that happens, satellites should be trained on the piece of the sky where plane was last seen, ground control should be alerted and tracking from the satellites performed. Clouds could be a problem, but planes are probably visible on SAR?

[logifail]

> Physical access can generally circumvent any security precautions, but it seems like there are some fairly simple schemes that would work well to prevent a disturbed captain

I can't be the only one thinking that in the situation where we postulate losing trust in the captain, whether tracking is switched on or not is a relatively minor issue, compared with - say - the captain deliberately flying the aircraft into a mountainside.

[ozr]

You're definitely not wrong. Most civil aviation authorities I'm aware of have some profound issues with their policies around pilots and mental health issues. Fixing that is more likely to prevent the issue in the first place. That's closer to the root cause and something that shouldn't be ignored.

But parallel to that (and unfortunately-but-most-likely in lieu of): we simply shouldn't be losing large aircraft and having no idea what happened.

[bombcar]

The biggest issue with all policies is the same with red flag laws - and even attempted mention of potentially having an issue grounds you and you lose your job; this makes the issue that much worse.

[logifail]

> we simply shouldn't be losing large aircraft and having no idea what happened

Maybe it doesn't nearly happen often enough to make this any kind of a priority?

[bombcar]

Which has occurred - perhaps if we actually want to try to control for “insane pilots” there has to be some way for someone on or off the plane to force it into autopilot with cat 5 autoland at the nearest airstrip.

[ipython]

… which then extends the critical flight controls security surface area to entities on the ground that have no vested interest in my safety? No thank you, I’ll take my chances with the flight crew which in 99.99999% of cases are also interested in arriving home safely.

[kashunstva]

> force it into autopilot with cat 5 autoland at the nearest airstrip.

I think CAT III C ILS have the lowest (theoretical) minimums at 0/0, although I don’t think that designation is actually used; so let’s just say CAT III in general has the lowest minimums.

[ipython]

One could say that about all sorts of capabilities in an aircraft that, in normal operation, seems insane. Is there ever a valid reason to fly a cargo plane inverted? See https://en.m.wikipedia.org/wiki/Federal_Express_Flight_705 for the answer.

[WalterBright]

Airliners are simply not designed to fly inverted. In Tex Johnson's famous barrel roll of a 707, he kept positive g on the airframe at all times.

One problem with flying inverted is the bottom of the airplane tends to accumulate junk - nuts, bolts, dropped tools, lunch boxes, dead mice, etc. Turning the airplane over means all that junk falls into the machinery, potentially jamming it.

[ipython]

Right- in the FedEx case it was a last ditch effort to literally knock the suicidal flight crew member off his balance and regain control of the aircraft. If you have a 'nanny' computer telling you that you're unable to do that, those crewmembers may have ended up dead instead.

Point being, in an unforeseen emergency, allowing crews to override the normal safety mechanisms may in fact save lives.

[HWR_14]

Do we care about preventing a disturbed captain from preventing recording? They can already crash the plane and kill everyone on board. I don't really care about their record keeping in that instance.

[sidlls]

It's necessary to rule out mechanical and other system failures, i.e., to provide evidence that it was a disturbed pilot and not some other cause. Aviation incident investigations are quite thorough--orders of magnitude more rigorous than in the software industry in general.

[pas]

it seems much more important to have a clean and unambiguous record than to start the usual finger pointing

[hungryforcodes]

> The difference is that the mh370 pilot deliberately took actions to avoid tracking.

I'm sorry, when did we decide this? As far as I can tell this is just one of a number of different theories on MH370s disappearance.

[ipython]

It’s obvious that we cannot know for sure since we have not found the wreckage, but no other theory I’m aware of can fit the facts as we know them.

[hungryforcodes]

It's because he's Muslim huh?

I mean there are lots of theories.

https://www.salon.com/2023/03/10/mh370-malaysia-plane-disapp...

My favorite is still the one about the fire caused by the windshield electrical heater. There is precedence on other Boeing 777s for this to have played out. It was a known problem.

If it really was a suicide drop into the ocean...why wait 8 hours...just...do it...

[ipython]

Wow. That escalated quickly. It has nothing to do with the fact he was Muslim and everything to do with the fact that there were no attempts to contact other planes or atc for help. I do not appreciate your false assertion and encourage you to retract your statement.

I am not an expert in the 777 electrical systems but the two minute delta between the last radio transmission - where there were no audial warnings and the pilots were calm - and the transponder ceasing to transmit seems unreasonable for a catastrophic event to take out these systems.

[tredre3]

> It's because he's Muslim huh?

The backhanded racism would have went: muslim + pilot = crash in building, not disappear in ocean. So clearly you're just trying to have a hot take here.

> If it really was a suicide drop into the ocean...why wait 8 hours...just...do it...

Even though someone might conclude that death is the preferable outcome for their situation, it doesn't mean that they won't experience an insane amount of anxiety and spend a long time reconsidering or even trying to talk themselves out of it just before pulling the trigger so to speak. They're humans until the end, with human reactions, you know?

[Jyaif]

> A more apt comparison would be AF447, which took a few days before the wreckage was found

it took more than a year to find the wreckage of AF447 and the black box (as per both TFA and your wikipedia link)

[ipython]

Thank you. I can’t edit my post now to correct myself unfortunately.

[mariuolo]

> A more apt comparison would be AF447, which took a few days before the wreckage was found.

Days? I thought it was found after two years.

[tristanb]

We absolutely do not know the captain did anything malicious , and he could have been a hero. So let’s not make statements like that.

[nix0n]

The current theory is that the pilot of MH-370 was able to disable most of the tracking equipment, while the plane moved away from any major population centers.

The radio operator of the Titanic was trying very hard to let everybody know where they were.

[faangsticle]

Why was he able to? Isn't the black box supposed to be a black box?

[dghlsakjg]

The black box has nothing to do with the transponders and tracking equipment.

The black box can’t be disabled AFAIK.

The argument in favor of disabling tracking is that the equipment itself could potentially malfunction in a way that disabling it would be safer (if it were interfering with voice communications or transmitting an emergency code inappropriately).

I fly small planes and it is not unheard of for ATC to ask pilots to cycle the power on a transponder that isn’t responding as expected. I assume that airline grade equipment is more reliable, but the same principle applies

[rtkwe]

There are two components, one is the Cockpit Voice Recorder which can be disabled because it's powered from the main system and records on a 2 hr loop that may need to be preserved if there's some incident that isn't a crash. The other is the Flight Data Recorder which isn't on a circuit breaker and records on a similar loop but is more of a crash system so they just run until there's no power on the plane for some reason.

[MAGZine]

AFAIK, the FDR and CVR can both be disabled by crew to some degree. I think they can be disconnected from the aircraft's power system (by fuse/breaker), but they also have some amount of battery backup.

Part of Federal Express Flight 705's whole debacle was that the hijacker tried to pull the breaker on the CVR.

And the investigation into SilkAir 185 was hampered because the recorders had their power pulled as a apart of load shedding while trying to resolve issues onboard the aircraft.

[bombcar]

The black box doesn’t transmit its location. If they find it, it would/will tell you some of what happened, but if you sink it in the Mariana Trench and they can’t find it, you’ve “won”.

[kube-system]

The black box can also transmit its location, albeit only after the plane hits the ocean: https://en.wikipedia.org/wiki/Underwater_locator_beacon

[teraflop]

> show a sinking titanic was heard both in london and new york, but a modern(...ish) MH-370 can just dissapear?

What do you mean by "heard both in London and New York"? The Titanic was actively sending out distress signals via telegraph as it sank, but those signals weren't strong enough to reach land. They were picked up by other nearby vessels and relayed.

[Gordonjcp]

It was night time. Titanic's radio transmitter could work on both 500kHz and 1MHz, pretty advanced stuff for the time, and the bands were far quieter.

It would have been hard *not* to hear it on both sides of the Atlantic, even with the primitive receivers of the day.

[kQq9oHeAz6wLLS]

Plus, lower frequencies generally have an easier time traveling long distances, especially over saltwater (and at night, hence the first part of your response).

And to answer the question about why we can't use lower frequencies on planes, part of the answer lies in antenna length, which is related to wavelength. Lower frequency = longer wavelength, which in turn means larger antenna (yes, I know this is a very broad generalization, and also not the complete/only reason). Look up the antenna required for 1Mhz.

[Gordonjcp]

The lowest band my amateur radio licence allows me to use is 136kHz, which would require a dipole about 1km long and at least 50m off the ground.

You wind a loading coil on a plastic dustbin.

[dylan604]

>via telegraph

?? Is there a different meaning of telegraph than I’m familiar that works without direct connected wires?

[detaro]

wireless telegraphy was/is a common name for sending text (especially as morse etc signals) over radio

[FreshStart]

So why can't we have aircraft screams some data in a last ditch effort?

[touisteur]

As long as you trust the pilot with absolute authority over which equipment is running, this isn't going to happen. If something can catch fire (as in, any electronics?), it needs to have some kind of local breaker that the flight crew can switch off. The only trusted equipment there is one doing passive recording of some elements (the flight recorder).

[bombcar]

The airframes do usually have various ELTs and beacons that can activate in a crash, but some (most?) can be disabled in some way (in case they’re accidentally on) - and others are only short range/directional.

[dghlsakjg]

We do. The radios they use can be heard for quite a distance at the altitudes they operate at

[nine_k]

Titanic was in the middle between London and NYC, relatively easily within reach of either by using longer waves. Titanic actively sent distress signals.

MH-370 has flown into the uninhabited area of Southern Indian ocean, far away from any places where a shorter-wave signal would be easy to receive, due to the curvature of Earth. MH-370 apparently did not send any distress signals; if it did, these would likely be received and relayed.

[antonjs]

I was surprised after MH370 that there isn't a beacon or flight recorder on the surface of the plane, that's buoyant and detaches on immersion.

Though I assume the engineering and regulation means such a thing has a decade+ lead time and then would only exist on new planes.

[ianburrell]

Aircraft have ELT that broadcast location. They are similar to the marine EPIRB or hiking PLB.

MH370 had 4 ELT, 2 on life raft, 1 in cabin, and 1 mounted to aircraft. The latter would have activated on crash but it was designed for ground crash not ocean. It would have sunk with plane. The life raft ones are water activated but probably sunk. ELT are more meant for finding survivors and not the crash site.

There are ejectable beacons but they are probably not required. It would make sense to add one for water crashes.

[pmarreck]

MH-370 was a suicidal pilot who deliberately disabled tracking mechanisms, my dude. Not sure if you got the memo

[Gud]

We don’t know that.

[omurphy27]

The pilot had a similar route to the one flown by MH370 on his home flight simulator according to the ATSB report. From Reuters:

"Six weeks before the aircraft’s disappearance, Captain Zaharie Ahmad Shah used his home simulator to fly a route that was initially similar to part of the route flown by MH370 up the Strait of Malacca, with a left-hand turn and track into the southern Indian Ocean, the ATSB said in its report."

It's highly likely that MH370 was the result of pilot suicide.

[IMSAI8080]

Indeed. Pilot suicide is just one theory and is not proven fact. Almost everyone thinks there was a decompression event on the aircraft. Another possibility is hypoxia causing pilot impairment as a result of decompression. Hypoxia severely inhibits brain function and turns you into an incompetent. It's similar to being extremely drunk or high on drugs. This happened on the Greek Helios flight that decompressed. The pilots can be heard on the recording becoming gradually unable to competently fly the plane and making ridiculous decisions due to brain impairment.

[sokoloff]

> Almost everyone thinks there was a decompression event on the aircraft.

I would wager that far more people believe in the suicide theory than an un-commanded decompression event.

[IMSAI8080]

It's a fairly common incident. There's a list of them:

https://en.wikipedia.org/wiki/Uncontrolled_decompression

[valval]

I imagine most airlines have operated at unsustainably low margins for the past however many years, at least here in Europe. Ticket prices have gone way up now, and I suppose it’s getting better for them.

[rocket_surgeron]

>Is there some good explanation, show a sinking titanic was heard both in london and new york, but a modern(...ish) MH-370 can just dissapear?

If Titanic had sunk in the Indian Ocean, it would probably still be lost.

By sinking in the North Atlantic it was within radio range of dozens of other ships and ground stations. Carpathia got to it in 3 hours.

The part of the Indian Ocean that MH370 is thought to have gone down in is second only to the South Pacific in emptiness.

[deepsun]

ADS-B has the same problem -- it's hard to collect it over the oceans.

Satellites do pick up the signal, but the detection area is pretty wide, so sometimes it's just too many signals coming in all at once, overwhelming the satellite. ADS-B is also pretty chatty, so the data sizes are significant (compared, to, say AIS, which is a similar system for marine vessels).

It's gradually becoming better, satellites having more focused antennas able to gather signals only from unpopulated areas, and more computing power to filter noise out.

[throw0101b]

> Satellites do pick up the signal, but the detection area is pretty wide, so sometimes it's just too many signals coming in all at once

Even with something like Aireon (that piggybacks on top of many Iridium sats)?

* https://en.wikipedia.org/wiki/Aireon

[deepsun]

I don't know how their system works, sorry. And whether they have 100% globe coverage.

[xen2xen1]

Yeah, my first thought in reading the article: maybe SpaceX and all the other constellations with make it cheaper to constantly stream data, and just use the expensive satellites for low speed backup. It looks like big planes will all end up with fat internet pipes for the passengers, let's hope that soon extends to avionics info.

[choppaface]

Why is the cost of sending data such an obstacle? It seems like that reporting should be done according to regulation .. do governments not subsidize the cost? Or perhaps it’s even just hard to get international alignment on this topic?

[roeles]

Would it make sense to broadcast vital information to "nearby" aircraft, so they can store and forward when something went wrong?

[pmarreck]

Wouldn't Starlink lower this cost tremendously?

[bnycum]

Currently the upcoming Starlink for Aviation terminal is for much larger aircraft than we are operating on at the moment. Plus the cost is $150k for hardware, and up to $25k monthly.

https://www.starlink.com/aviation