With today's technology why is CVR and FDR information still stored on airplanes this data should be broadcast back to a ground based computer system and then when the data hits a date 30 days or older without being accessed it gets erased. I just don't get it really.

klm617 wrote:

With today's technology why is CVR and FDR information still stored on airplanes this data should be broadcast back to a ground based computer system

Money.

Because the cheap data link technology doesn't exist for much of the world. Even parts of the United States have gaps which would require satellite data links.

Another thread quoted prices for real-time high-speed internet for private jets across the North Atlantic - $20,000 per flight or more.

Automated data backup could easily equal that costs.

Then the amount of data to be backed up - FlightAware currently shows over 2,800 commercial flights in the air over the US. That's a need for hundreds of terabytes of data storage per hour.

Could it be done - probably for most of the populated world airspace. For transoceanic routes - possibly some data backups. Complete data backup is going to require new satellites over many ocean areas.

There are companies working on the technical solutions. So far they've demonstrated a capability for doing such backups over land with plenty of cell towers located below the aircraft. Less reliability using satellite links.

rfields5421 wrote:

Another thread quoted prices for real-time high-speed internet for private jets across the North Atlantic - $20,000 per flight or more.

Automated data backup could easily equal that costs.

Then the amount of data to be backed up - FlightAware currently shows over 2,800 commercial flights in the air over the US. That's a need for hundreds of terabytes of data storage per hour.

Please . Give us a break.
That people on the private jet were watching video/doing videoconference. Video is inerherntly heavy. It was so 30 years ago when I was in the Signal Corps, and still it is, with the more modern lossy compression technologies like Mpeg.
Nobody in their right mind is proposing to live videoclip the pilots during the flight, today, at least.
What about textual data, like the one in the ACARS? From back of envelope calculation:
A page full page 80x25 char is 2kB, but highly redundant, I bet it can be lossless compressed down to 1k (or much less).
One transmission per minute x 2800 aircrafts = circa 3 MB/ minute with overhead = circa 180 MB /h. My USBpen drive can store days of it.
If you want to use more conventional notation we are speaking average bandwidth use of circa 500 Kb/s. My single USB 3G modem is doing more than that in this precise moment.
Is the satellite network able to do that?
Are we able to store such "impressive"amount of data for a while?
Are the costs involved manageable once diluited on the 2800 x 100 = circa 300,000 users (passengers) in that moment?
My bet is that they are. Just the system is resilient to innovation and has no incentive to do it, if the regulator does not take over.
And I a.net is even more so, I remember I went out with similar proposals at the time of AF447, and all the baseless s%&t that I received.
Now, seven years later, nothing has changed.
So please do not get upset if I will not comment further on the argument.

One transmission per minute means you might be losing 59 seconds of data. Frequency would need to be higher than that.

Modern FDR's record over 2048 words per second in 8 bit format. Each hour of FDR data is over 1 GB in size. A 32GB FDR is only spec'd to record 25 hours of flight data.

A 32GB CVR records only 120 minutes of voice from four input sources.

ACARS data normally consists of one four character code for an event. The code readouts we see such as right windshield heat or smoke in the avionics bay are post receipt processing of the ACARS codes. ACARS has no ability to transmit data for unanticipated events. The event and code have to be pre-programmed into the system on both ends.

FDRs record data to the limits, high and low, of the sensor devices. CVR data is of course little actual voice recording, but noises of movements of controls, buttons pushed by the crew, alarms, advisories, etc - are important parts of accident investigations.

rfields5421 wrote:

Modern FDR's record over 2048 words per second in 8 bit format. Each hour of FDR data is over 1 GB in size.

Not saying you are not correct but your math does not hold.
2kB Data per second is only 7.2 MB per hour.While 60 times more than my example,still a very small amount of data. Like your average 16 mpix foto once jpegged. Per hour.
But this is not my point. That is that with a very small bandwidth you can transmit a ton of info about position and relevant events. Voice as well. Not intended to fully replace a FDR /CVR .BW and storage costs are NOT the problem and are negligible once spreaded between the users.Sorry to have intervened again for the sake of clarity only. I know that this is tabu.

If you dont want to replace both FDR and CVR completely, it doesnt make much sense to put it on-line.
Because, at one point, investigators will want that one piece of info that is missing, lost in transmission or in compressing. Example: ACARS doesnt give more than an indication, not a solution.

Anyway, with only 2kB of data you still need the FDR/CVR, so where is the gain?

o0OOO0oChris wrote:

According to AVHerald, the ACARS-sequence was:

00:26Z 3044 ANTI ICE R WINDOW
00:26Z 561200 R SLIDING WINDOW SENSOR
00:26Z 2600 SMOKE LAVATORY SMOKE
00:27Z 2600 AVIONICS SMOKE
00:28Z 561100 R FIXED WINDOW SENSOR
00:29Z 2200 AUTO FLT FCU 2 FAULT
00:29Z 2700 F/CTL SEC 3 FAULT

For me that sequence looks like a fire that started when the right window anti ice overheated.

Anti ice overheats, starting a fire, after a while it fails completely, giving the first message
Then fire takes out the window sensor
Then the fire continues to spread

But what speaks against it is: How could something flammable be in or close to the window?

The post I was replying to commented on why is FDR / CVR data kept aboard the aircraft. The person said that with current technology - all that data could be broadcast from the aircraft and recorded on the ground. I disagreed.

Current FDR/ CVR recording consists of a maximum of 25 hours for FDR data - all that can be held on 32GB of protected shock resistant memory. And two hours of CVR data in the same amount of memory. Those are public specs of FDR/CVR devices from several companies. You can find them on the internet.

This subject has been discussed in depth in the past, and as I said - companies are working on getting to the point eventually where it will be possible.

But current technology is not good enough to either provide the reliability to replace the FDR/ CVR with ground based data storage at an economical rate. The currently available systems require broadcast of the data to a ground based data network antenna, unless something has been announced that I haven't seen.

Will we get there at some point? Possibly.

Lets just assume that such technology is available for $2,000 per aircraft for equipment retro-fit and $5,000 per month per aircraft for data usage rates. For an airline like American Airlines - that is 1.9 million dollars for aircraft - and $57 million per year for data usage. That is still a significant costs.

This question always comes up when aircraft are lost over water outside VHF radio range (which may not apply to this flight). The reality is that much of the world is not readily accessible to consistently reliable satellite data technology.

rfields5421 wrote:

A 32GB CVR records only 120 minutes of voice from four input sources

Wow - that surprises me!

CD audio quality (uncompressed/linear PCM) is less than 0.7 GB per hour (for 2 channels).
4 channels * 2 hours in CD quality is roughly 2.5 GB.

I can see the need to store the data with lots of redundancy, in case the storage unit is damaged, and that will increase the amount of data. Maybe they also want higher resolution than 44.1 kHz/16bit - since they have cheap storage onboard anyway. But if you want to stream the data off the plane, this way of thinking wouldn't make sense - you're not going to add redundency data that makes the transmission more than 10 times larger than the original data. You'd rather compress the data.

So, maybe the same applies to the FDR data:

rfields5421 wrote:

Each hour of FDR data is over 1 GB in size.

...maybe there's a lot of redundancy in the storage process, and that the actual data is a lot smaller? (And can get even much smaller with compression?)

Like I've said before, you don't need to transmit ALL the CVR/FDR data via satellite. Off the top of my head, the most important data you need is location, speed, altitude. If you have this, finding the wreckage will be much easier. And please don't tell me it costs thousands of dollars to transmit this most basic data. That is absurd. If those three parameters were being transmitted (even if it cost a few hundred dollars) we wouldn't now be spending 2+ years and hundreds and hundreds of millions of dollars and frustration on finding MH370. A majority of the Earth's area is considered "remote" and out of VHF radio range when you really think about it. In addition, transmitting via satellite doesn't need to happen on all flights. There's no point of this if you're flying JFK-ORD or something. But it should be made mandatory for flights over large areas of open water, remote mountains or desert, Arctic regions and etc. That's a fraction of all flights and won't break the bank.

Transmitting basic course, speed, altitude, position data is already a part of the ACARS system. Flight24 and FlightAware might not be in business without that data transmission being a standard.

That is how the searchers knew where to look for AF447. Just nobody thought to look behind the last reported position where we eventually learned the aircraft had backtracked several miles during its descent. But at the time Air France had set their system to send such data every ten minutes.

Even with that interval, it was very common for several position reports to not be received in certain areas of the world.

My memory might be wrong, but I seem to remember two issues with MH 370. One was that the airline choose to not pay for extensive data coverage services, and the second is that for unknown reasons the equipment that transmits that type data stopped functioning immediately when the tracking of the aircraft was lost.

There are detailed technical discussions of the tech, operational methodology, reliability issues and costs in the threads on the two crashes.

The AF 447 investigation reports are especially disturbing in that they reveal Air France maintenance reported to AF ops very soon after the last data transmissions that the aircraft might be in danger. Yet it was over seven hours before an ATC official cut across the red tape and issued an alert for a missing aircraft.

rfields5421 wrote:

The AF 447 investigation reports are especially disturbing in that they reveal Air France maintenance reported to AF ops very soon after the last data transmissions that the aircraft might be in danger. Yet it was over seven hours before an ATC official cut across the red tape and issued an alert for a missing aircraft.

How was communication in that area between aircraft and ATC? I can't remember now from the myriad of threads and posts but it seems like there are spots where they are not in direct contact for periods of time. If that's the case, I can understand in a basic sense why they might choose to wait for further information rather than raise alerts immediately. 7 hours? Not sure if that's explainable though.

Communication is by HF radio. Also the aircraft acknowledged handoff from Brazil ATC - but never checked in with Cape Verde Islands ATC. The emergency happened in that gap of time when the aircraft was trying to establish contact with Cape Verde.

For a few hours it was Brazil saying 'we handed the flight off - it safely passed out of our airspace' and Cape Verde saying 'we never got responsibility for the flight'.

AF Ops contacted another AF flight on the same path a bit behind AF447 and ask them to try to contact the aircraft on VHF/Guard.

The AF447 reports go into some detail on the confusion, the 'its my territory / its not my responsibility because the flight never contacted us' arguments, and the final decision by an ATC official in Spain to issue the alert for an area of ocean for which he had no authority. Though Cape Verde did issue an alert a few minutes after the initial one from Spain. Makes good/ scary reading.

While a prompt alert and dispatch of SAR resources would have made no difference in that, or most of the other "missing over water aircraft" - it is scary to realize that in the unlikely event crew/ passengers ever survived an open ocean landing - it could be several hours before people start to look for them.

Transoceanic areas like the Atlantic, Pacific and Indian Ocean have many different nations with zones of responsibility - yet no one has total control / responsibility for the entire ocean / flight route. No one can demand coordination, action, accountability.

There was some formal discussions on how to improve the process. We will not know how those changes are applied until another aircraft is missing over a similar region.

planewasted wrote:

o0OOO0oChris wrote:

According to AVHerald, the ACARS-sequence was:

00:26Z 3044 ANTI ICE R WINDOW
00:26Z 561200 R SLIDING WINDOW SENSOR
00:26Z 2600 SMOKE LAVATORY SMOKE
00:27Z 2600 AVIONICS SMOKE
00:28Z 561100 R FIXED WINDOW SENSOR
00:29Z 2200 AUTO FLT FCU 2 FAULT
00:29Z 2700 F/CTL SEC 3 FAULT

For me that sequence looks like a fire that started when the right window anti ice overheated.

Anti ice overheats, starting a fire, after a while it fails completely, giving the first message
Then fire takes out the window sensor
Then the fire continues to spread

But what speaks against it is: How could something flammable be in or close to the window?

Just because messages related to Windshield Anti-Ice faults are captured, one cannot automatically assume the problem originated at the window itself. Those sensors on the windows go back to some sort of window heat controller where the monitoring actually takes place and where a signal is generated to show a fault. A break in that wiring anywhere from the controller to the windows could cause those messages, or possibly at the controller itself. Does anyone know where the window heat controllers are on the A320? I don't recall from my time working on them. If thy are down in the forward avionics bay, it's quite possible that those messages are just collateral damage from whatever happened in the lav or avionics bay and totally unrelated to what took down the aircraft.

Don't forget also, if you consider an actual fire in the cockpit, the crew oxygen mask is in that area .. if there's a fire, and the oxy system is compromised (and starts spewing O2), that'll drastically catalyze the fire.

When they tested the fire conditions for Valujet 592, the oxygen emitted from the oxy canisters feeding the fire pushed it to levels that almost exceeded the ability of the testing chamber to contain it ... e.g., they almost burned down the test facility.

The temperatures reached aren't even known, because they maxed out the measurement devices.

Regarding crew oxygen - does the FDR and/or ACARS record activation and usage of that system?

rfields5421 wrote:

Transmitting basic course, speed, altitude, position data is already a part of the ACARS system. Flight24 and FlightAware might not be in business without that data transmission being a standard.

This is not true. The position information your are talking about comes from ADS or CPDLC which uses ACARS network to carry the information. ACARS is just a network with VHF ground stations and satellite gateways.

FR24 etc use different technology again, either a data feed from the FAA etc or ADS receivers that enthusiasts forward onto their networks from across the globe.

What is being rolled today out is ADS receivers on low earth orbit satellites which will enable global ADS coverage without needing any modification to aircraft already ADS equipped.

Soon we will have the ability to globally track all ADS equipped aircraft. However not all ATC units will use the data as they don't have the ground equipment, trained controllers, or want to pay for the cost.

The cost for providing air traffic services always has been the responsibility of government not industry. The airspace belongs to the state not industry.

The other problem with satellite based broadband is its not global. That is why aircraft use HF datalink when on polar routes.

sovietjet wrote:

Like I've said before, you don't need to transmit ALL the CVR/FDR data via satellite. Off the top of my head, the most important data you need is location, speed, altitude. If you have this, finding the wreckage will be much easier.

And like I've said before, I'm not sure why you or anyone thinks an airplane will continue transmitting this after it's lost the electrical power that allows it to already transmit its position, speed and altitude via ADS-B to ATC. What *exactly* are you asking for that's not already being done?

And was this airplane not found using this exact data set?

spacecadet wrote:

And like I've said before, I'm not sure why you or anyone thinks an airplane will continue transmitting this after it's lost the electrical power that allows it to already transmit its position, speed and altitude via ADS-B to ATC. What *exactly* are you asking for that's not already being done?

For a system with infinite power source and infinite datalink capabilities and the intelligence to sort only the relevant facts from the mountains of data being streamed to the FDR... of course!

spacecadet wrote:

And was this airplane not found using this exact data set?

D'oh! You and your pesky logic...

Looks like we will have some news soon.

The crash site of EgyptAir Flight 804 deep in the eastern Mediterranean has given up all its secrets. Investigators into the crash now have a complete and detailed map of the field of debris. The Daily Beast can reveal that the specialized deepsea search vessel John Lethbridge has completed its mission and left the area after completing the mapping.

Although Egyptian officials have yet to announce what has been disclosed by data downloaded from the flight recorders of the Airbus A320, the picture of the debris field is equally important to understanding what happened. Small details can provide big clues—in this case the role that control surfaces played when pilots lost control of the flight.

Source:
http://www.thedailybeast.com/articles/2016/07/20/investigators-find-vital-new-clues-to-egyptair-804-crash.html

spacecadet wrote:

sovietjet wrote:

Like I've said before, you don't need to transmit ALL the CVR/FDR data via satellite. Off the top of my head, the most important data you need is location, speed, altitude. If you have this, finding the wreckage will be much easier.

And like I've said before, I'm not sure why you or anyone thinks an airplane will continue transmitting this after it's lost the electrical power that allows it to already transmit its position, speed and altitude via ADS-B to ATC. What *exactly* are you asking for that's not already being done?

And was this airplane not found using this exact data set?

What I'm asking that isn't already done is transmitting a snippet of simple text information containing the most important position related parameters via SATELLITE not ADS-B. ADS-B doesn't work in the middle of the ocean. And nowhere did I say it needs to happen after the aircraft lost electrical power or crashed. But the information received until the moment that happens would be crucial in finding the crash site.

Read my reply 318, ADS-B will soon be available over oceans via low earth orbit satellites.

http://aireon.com/services/global-air-t ... veillance/

this is an interesting quote from the article linked above ...

First priority of the search after the retrieval of the flight recorders was to use the ROV to get close-up images of the forward section of the A320’s fuselage, including the flight deck. This quickly established that there was evidence of heat damage, possibly from a fire

If there is evidence of burn-through visible from the ROV pictures, that could shed a lot of light concerning the level of fire and intensity.

Is it possible that the chain of events happened slower than we are expected to believe because the flight crew was doing something there were not suppose to be doing in the cockpit or had something up front that was not allowed and as the emergency unfolded they were trying to defuse it without calling a mayday to cover up what it was that caused the fire to break out in the cockpit.

klm617 wrote:

Is it possible that the chain of events happened slower than we are expected to believe because the flight crew was doing something there were not suppose to be doing in the cockpit or had something up front that was not allowed and as the emergency unfolded they were trying to defuse it without calling a mayday to cover up what it was that caused the fire to break out in the cockpit.

I lost count at about 60 words in that sentence, but after reading it again I think your questions will best be answered by the final report.

UPDATE:
As per NYTIMES,

EgyptAir Flight 804 Broke Up in Midair After a Fire, Evidence Suggests

Excerpt from the article:

CAIRO — Evidence gathered in an investigation into the crash of EgyptAir Flight 804 in the Mediterranean Sea in May indicates that the plane most likely broke up in midair after a fire near or inside the cockpit that quickly overwhelmed the crew, according to Egyptian officials involved in the inquiry.

But the officials could not determine whether the fire thought to have caused the crash had been set off by a mechanical malfunction or by a malicious act....

Story continues here:
http://www.nytimes.com/2016/07/23/world/middleeast/egyptair-804-crash-fire.html?_r=0

spacecadet wrote:

PeterB wrote:

Maybe I missed something in your argumentation. You rule out terrorism because they tried to extinguish a fire ? This doesn't make any sense! Unless it is not clear what the source of the fire was you cannot rule out anything! The source of the fire could have been a bomb as well.

It technically could be, but think about what a stretch of logic that is at this point. Setting an on-board fire through the use of some sort of incendiary device is not a tactic any terrorist organization has used before. And the reasons are obvious - it's not that they haven't thought of it (if you or I have, they have). It would be a really unreliable way of downing a plane, for one thing - pilots and even planes themselves have equipment to fight fires, and lots of planes have landed safely with a fire on board. Others have not, but is that a chance a terrorist is going to take?

Just because this technique has not been used before does not rule it out.
They never used aircraft as cruise missiles before 911 either. They never used box cutters as primary weapons before 911 either.
I don't remember them using trucks to mow down people either.

As far as reliability. I don't think they care that much. If it doesn't work - so what. If it does - then they win.

rcair1 wrote:

As far as reliability. I don't think they care that much. If it doesn't work - so what. If it does - then they win.

You have to take off your shoes and have them scanned before boarding a commercial flight - because of an unreliable failure of an attempt to bring down a plane.

You have to walk through a metal detector, which usually includes sniffers for explosive compounds, and senior citizens who wear diapers get detailed searches often - because of an unreliable failure of an attempt to bring down a plane.

Terrorist do like the visible successes of exploding planes - but even more - they like forcing you to live your life differently and in fear - because they might be successful with the next wild idea.

Just as important for terrorists is making the world aware that they did cause the incident which makes you fearful.

(Not that I believe or have seen anything which indicates this crash was anything other than a very unfortunate mechanical/electrical failure.)

Some new reports coming up:
http://www.ibtimes.co.uk/faulty-phone-b ... ay-1600963
Quote:
According to The Times, CCTV pulled from cameras at Paris' Charles de Gualle airport show that the co-pilot stored a number of personal items above the dashboard, where the first signs of trouble were detected. .....

A source from the investigation told Le Parisian that they were investigating links between where the co-pilot placed his items and the spot where the fire started. "The images show very clearly that the Egyptian co-pilot placed his telephone, tablet and bottles of perfume bought before boarding on the glare-shield," the newspaper said.

"The investigators thus note a troubling parallel between the placing of these items that are fed by lithium batteries and the triggering of alarms during the flight."
Sounds plausible and fit`s to my theory on reply #298.
Bottles of perfume would feed a phone-ignited fire nicely.

On pprune someone posted rumors that the 777 fire may have been fed by parfume bottles too, used for cleaning hands after eating something (which he claimed is an islamic habit. https://en.wikipedia.org/wiki/Sunnah https://sunnahaday.wordpress.com/2010/1 ... you-sleep/)

I doesn`t sound like a good idea to bring and store something flammable in the cockpit. Make`s the whole effords of engineers to create a fire retardant environment on an airliner pointless.

hmmm

arent those electronic devices usually known for flaming up
- during loading or
- in case of bent or crushing

neither of these seems probable near the cockpit side window, does it?

Could a lithium fire flare up and become uncontainable so quickly? If it were in front of the pilot (or above his head?) the pilots would have realized it quickly and taken action. Don't the airlines have procedures and canisters for neutralizing or at least isolating burning cell phones? Perhaps the perfume was the catalyst, but it seems odd that a lithium fire could take over the aircraft so quickly.

I hope he didn't have a Samsung 7!

JAAlbert wrote:

I hope he didn't have a Samsung 7!

Exactly my thought after reading the speculation! It would be very interesting to know what kind of phone it was.

asdf wrote:

hmmm

arent those electronic devices usually known for flaming up
- during loading or
- in case of bent or crushing

neither of these seems probable near the cockpit side window, does it?

As long as the battery is being used, and sometimes even if it is not (outside the device even) it can go boom. It's a chemical reaction.

I have never experienced this, but sometimes my phone gets hot, even though I'm not using it (but it's always doing something of course).

asdf wrote:

hmmm

arent those electronic devices usually known for flaming up
- during loading or
- in case of bent or crushing

neither of these seems probable near the cockpit side window, does it?

Damaging the device will make a fire more likely, but the 787 batteries weren`t damaged and yet they had a runaway.

Li batteries don`t like heat. A phone battery get`s warm in operation, due to it`s own losses and due to proximity to ic on the board getting warm. My phone battery has a temperature of 34°C right now, 14°C above room temp.
If there was a contact to the windshield with it`s heaters, it may have gotten too hot. Some search result`s on google state that the windscreens are heated to 42°C, add 15°C on top of that for it`s own heatemissions you`ll get to 57°C, pretty uncomfortable for Li batteries making a failure more likely.

I thought it was determined that this crash was a result of a bomb.

Per United Press, the co-pilot was carrying an iPad and an iPhone, along with several bottles of perfume in his carry-on bag. French investigators have, according to the French press, singled out these items as potential ignition sources of an inflight fire in the cockpit.

Source: http://www.upi.com/Top_News/World-News/ ... 1484325737

stasisLAX wrote:

Per United Press, the co-pilot was carrying an iPad and an iPhone, along with several bottles of perfume in his carry-on bag. French investigators have, according to the French press, singled out these items as potential ignition sources of an inflight fire in the cockpit.

Source: http://www.upi.com/Top_News/World-News/ ... 1484325737

It must have been frightening in that cockpit when the fire broke out and they couldn't extinguish it. I wonder if the fire destroyed the flight controls, or whether the smoke incapacitated the pilots or whether the pilots lost control of the plane while distracted by the fire.

Dreamflight767 wrote:

I thought it was determined that this crash was a result of a bomb.

No it wasn't. The Egyptians are claiming that to avoid blame.