Modern forms of FDR and CVR implementations
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Modern forms of FDR and CVR implementations
Moving this away from the MH370 thread, I was wondering what people's views are on the modernisation of the FDR/CVR function in passenger jets.
Since when they were first used in aircraft, their sole purpose was to provide post crash evidence of of aircraft state and comms after an accident. The possibility of deliberate disablement of these pieces of equipment was not really considered.
Now with the rise of terrorism, and a growing increase in the terrorist's apparent technical prowess, these simple recorders are showing their inadequacy.
Is this an issue that is being addressed in current/future aircraft design? clearly the possibly storage of FD/CV data remotely, ie enhanced ACARS style, is a possibility, but requires additional bandwidth and is subject to potential disruption from persons on board.
Thoughts anyone?
Since when they were first used in aircraft, their sole purpose was to provide post crash evidence of of aircraft state and comms after an accident. The possibility of deliberate disablement of these pieces of equipment was not really considered.
Now with the rise of terrorism, and a growing increase in the terrorist's apparent technical prowess, these simple recorders are showing their inadequacy.
Is this an issue that is being addressed in current/future aircraft design? clearly the possibly storage of FD/CV data remotely, ie enhanced ACARS style, is a possibility, but requires additional bandwidth and is subject to potential disruption from persons on board.
Thoughts anyone?
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For a start both "black boxes" should be redundant having both FDR and CVR capability. That would double the odds of finding them and having readable data. Nowadays electronics are so small that the space and weight taken would be minimal. I think this is obvious.
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Indeed, one at each end of the aircraft.
further more (in very simplistic terms!) an existing automatically deployed ELT unit could be fitted with an "SD card" which is fed data from the FD/CVR pair in real time. the unit would be charged, and the data fed to it, via an inductive loop, obviating physical electrical connections to the aircraft's systems.
Assuming the ELT was found and recovered the SD card could be read. I suspect a high capacity SD card would probably hold months worth of voice and flight data!
further more (in very simplistic terms!) an existing automatically deployed ELT unit could be fitted with an "SD card" which is fed data from the FD/CVR pair in real time. the unit would be charged, and the data fed to it, via an inductive loop, obviating physical electrical connections to the aircraft's systems.
Assuming the ELT was found and recovered the SD card could be read. I suspect a high capacity SD card would probably hold months worth of voice and flight data!
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With thanks to NorthernKestral:
Royal Aeronautical Society | Insight Blog | MH370 ? implications of a ?Black Swan? aviation event
Royal Aeronautical Society | Insight Blog | MH370 ? implications of a ?Black Swan? aviation event
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Profesional disscusion was taken few years ago.
Flight Data Recovery Working Group Report
Triggered Transmission of Flight Data Working Group
and of course Final Report of AF447 - look there for recommendations.
Triggered Transmission of Flight Data Working Group
and of course Final Report of AF447 - look there for recommendations.
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Already solved...CPI with FDR/CVR
No need for data streaming which will have issues with continuing subscriptions, bandwidth, privacy and dispatch/MEL issues. And it can still be disabled via a CB.
There are already floatable 406 MHz ELT devices with impact or pilot initiated release that include CVR/FDR.
Because they have an internal battery, they can't be turned off readily and can have tamper resistance.
The Crash Position Indicator just needs the industry and public will to be carried on jetliners.
Example at link (this is a low airspeed FDR model, but they have been mounted on jets too, with secondary CVR/FDR).
http://www.hr-smith.com/images/stories/503-CPI.pdf
There are already floatable 406 MHz ELT devices with impact or pilot initiated release that include CVR/FDR.
Because they have an internal battery, they can't be turned off readily and can have tamper resistance.
The Crash Position Indicator just needs the industry and public will to be carried on jetliners.
Example at link (this is a low airspeed FDR model, but they have been mounted on jets too, with secondary CVR/FDR).
http://www.hr-smith.com/images/stories/503-CPI.pdf
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Interesting stuff: thanks for the links. Looking at the data sheets it looks like the security would need to be beefed up a bit to prevent interference, but the functionality is there.
So, it would seem, as usual, that the bean counters are the cause of non deployment.
So, it would seem, as usual, that the bean counters are the cause of non deployment.
Last edited by JamesCam; 20th Mar 2014 at 21:08. Reason: Typo
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We are using obsolete solutions
Hi,
We are using obsolete solutions!
Not necessary an questionable.
Thoughts anyone?
...I think this is obvious.
remote reading
No need for data streaming
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Re: Beancounters
I suspect that back in the 70s there were enough "ordinary" mishaps that internal ELTs, CVR and FDRs were thought enough. The cost of wiring an external CPI and fairings didn't seem worth it, as most searches and investigations didn't need immediate answers, foul play was rare but conventional and usually obvious.
Today, in the current security environment and the rarity of "ordinary" mishaps, any mishap creates instant public obsession about the event (was it terrorism?) and demand for answers, right now!
Retrofitting a passenger entertainment system is supported by a business model, we want those movies and WiFi as SLF. The cost for a CPI would be less, if the public wants to pay for it.
If the wreck of MH370 isn't found, I think we will see something like CPIs be demanded by the public.
Today, in the current security environment and the rarity of "ordinary" mishaps, any mishap creates instant public obsession about the event (was it terrorism?) and demand for answers, right now!
Retrofitting a passenger entertainment system is supported by a business model, we want those movies and WiFi as SLF. The cost for a CPI would be less, if the public wants to pay for it.
If the wreck of MH370 isn't found, I think we will see something like CPIs be demanded by the public.
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Some thoughts
As an Electronics engineer although not involved in Aviation I have a few thoughts.
1) In order to retrofit at acceptable cost a plug and fitment compatible unit would be the favorite starting point.
2) weight saving might be used as an offset to the cost.
3)The storage would need to be unaffected by water and pressure.
4)Redundancy within the unit could be used to offset the possibility of damage to one storage device.
5)The lifetime of the sonar transmitter would ideally be extended possibly by use of a sonar receiver to trigger additional transmission.
PS. I have read that a larger capacity crash survivable memory unit may be readily available. It seems that this could be an immediately available improvement.
1) In order to retrofit at acceptable cost a plug and fitment compatible unit would be the favorite starting point.
2) weight saving might be used as an offset to the cost.
3)The storage would need to be unaffected by water and pressure.
4)Redundancy within the unit could be used to offset the possibility of damage to one storage device.
5)The lifetime of the sonar transmitter would ideally be extended possibly by use of a sonar receiver to trigger additional transmission.
PS. I have read that a larger capacity crash survivable memory unit may be readily available. It seems that this could be an immediately available improvement.
Last edited by Rory166; 21st Mar 2014 at 21:19. Reason: New Info.
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Improvement
5)The lifetime of the sonar transmitter would ideally be extended possibly by use of a sonar receiver to trigger additional transmission.
3)The storage would need to be unaffected by water and pressure.
4)Redundancy within the unit could be used to offset the possibility of damage to one storage device.
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Why not just modify ELTs
Given the costs of real time telemetry and things like the costs of SAR and FDR Recovery, wouldn't it be simplest to just to refit/redesign fixed aircraft ELTs (vs portable raft beacons) on extended overwater or ETOPS aircraft with automated smoke and pressure triggers? They would automatically transmit in flight in the event of a smoke or pressurization event and could be readily cancelled if the smoke was just a mitt in the oven or the pressurization loss was temporary.
If MA 370 was a fire or depressurization event SAR would have been notified hours earlier, we'd have been looking for the plane while it was still in the air, we'd know it's position more accurately, and in the event there were ever survivors in some other crash they would get quicker medical attention.
It seems like a reasonably cheap and effective solution, one that is much more likely to be acceptable to industry.
If MA 370 was a fire or depressurization event SAR would have been notified hours earlier, we'd have been looking for the plane while it was still in the air, we'd know it's position more accurately, and in the event there were ever survivors in some other crash they would get quicker medical attention.
It seems like a reasonably cheap and effective solution, one that is much more likely to be acceptable to industry.
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I think there's a fairly major point being missed here. From what I've read, flight recorder function (particularly with regard to the CVR, but also FDRs to some extent) was not initially proscribed by tech or cost considerations, but for legal/regulatory reasons. In the '60s and early '70s when CVR technology was first widely implemented, pilots' unions and organisations were incredibly resistant to making their presence mandatory - citing potential abuse by employers as a "spy" in the cockpit among other things. What was eventually hashed out was a set of regulations stipulating restrictions, including that CVRs were to be used only for accident investigation by the authorities, would hold no more than 30 minutes of audio on a loop, and that a "bulk erase" switch be fitted in the cockpit to be used on successful completion of a flight. The latter restriction was usually complemented by a further regulation stating that if the "bulk erase" switch was used for any other purpose, or at any other time, the crew would face severe penalties for doing so.
As technology marched on, I believe the only ground given was in extending the recording loop from 30 minutes to 120 (in the wake of accidents where the initiating event occurred more than 30 minutes before impact or landing). Meanwhile, as flight deck and recorder technology moved into the digital realm, FDRs went from recording ten parameters or less to tens of parameters, and by the '80s over 100 parameters were being recorded on new types with DFDRs.
Now I'm not a pilot, but I am a fairly frequent SLF. Heaven knows, if something happened to me as a result of an aviation accident or criminal act, I'd want people to know why. But on the other hand, the restrictions on the use of this kind of data are there for good reasons, and realistically any of these clever potential solutions would need to have their benefits weighed carefully against their drawbacks.
For the record, I remain sceptical of claims made regarding deliberate actions on MH370 - and without wanting to cause offence, I also regard the notion that terrorism is a greater threat globally now than it was before 2001 to be a little overstated. I certainly think that a lot of the changes made to aviation security since 2001 seem to be more about governments wanting to be seen to be doing something - and private agencies taking handsome payments for providing such services - than it is about finding a practical solution to the issue.
As technology marched on, I believe the only ground given was in extending the recording loop from 30 minutes to 120 (in the wake of accidents where the initiating event occurred more than 30 minutes before impact or landing). Meanwhile, as flight deck and recorder technology moved into the digital realm, FDRs went from recording ten parameters or less to tens of parameters, and by the '80s over 100 parameters were being recorded on new types with DFDRs.
Now I'm not a pilot, but I am a fairly frequent SLF. Heaven knows, if something happened to me as a result of an aviation accident or criminal act, I'd want people to know why. But on the other hand, the restrictions on the use of this kind of data are there for good reasons, and realistically any of these clever potential solutions would need to have their benefits weighed carefully against their drawbacks.
For the record, I remain sceptical of claims made regarding deliberate actions on MH370 - and without wanting to cause offence, I also regard the notion that terrorism is a greater threat globally now than it was before 2001 to be a little overstated. I certainly think that a lot of the changes made to aviation security since 2001 seem to be more about governments wanting to be seen to be doing something - and private agencies taking handsome payments for providing such services - than it is about finding a practical solution to the issue.
further more (in very simplistic terms!) an existing automatically deployed ELT unit could be fitted with an "SD card" which is fed data from the FD/CVR pair in real time. the unit would be charged, and the data fed to it, via an inductive loop, obviating physical electrical connections to the aircraft's systems.
That's enough for quite a lot of data storage, even plenty of room for recording video if you built a storage rack for a series of them about the size of a box of matches.
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CVR
I think most are in agreement that 2 hours is no longer enough for modern requirements and increasing this is just a matter of certifying and installing flash memory capable of a longer write/overwrite cycle.
10 hours (a more suitable length of time) of 5 audio channels recorded at CD quality (sampled in 16 bit at a frequency of 44KHz) would require just under 15 GB of memory.
10 hours (a more suitable length of time) of 5 audio channels recorded at CD quality (sampled in 16 bit at a frequency of 44KHz) would require just under 15 GB of memory.
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@18-Wheeler/SpeedofSound:
The problem with flash memory is that it doesn't take well to repeated writes of the kind that would be needed in a flight recorder - after a while you end up with bad cells, which is why modern solid-state devices still AFAIK use hardened IC storage designed for purpose. The issue with flash memory writes is improving with each generation of technology, but I don't think it's reliable enough for aviation use as yet.
Are "most" in agreement that 2hrs is no longer sufficient? I haven't seen anything to that effect, but I wouldn't know where to look. Is there a link handy?
Repeating what I said in my post above, the main issues are not necessarily technical, but legal and regulatory. Leaving MA370 to one side, are there any accidents in recent times where the investigation would have significantly benefitted from more CVR time, let alone offsite storage?
The problem with flash memory is that it doesn't take well to repeated writes of the kind that would be needed in a flight recorder - after a while you end up with bad cells, which is why modern solid-state devices still AFAIK use hardened IC storage designed for purpose. The issue with flash memory writes is improving with each generation of technology, but I don't think it's reliable enough for aviation use as yet.
Are "most" in agreement that 2hrs is no longer sufficient? I haven't seen anything to that effect, but I wouldn't know where to look. Is there a link handy?
Repeating what I said in my post above, the main issues are not necessarily technical, but legal and regulatory. Leaving MA370 to one side, are there any accidents in recent times where the investigation would have significantly benefitted from more CVR time, let alone offsite storage?
Hey, Doze! Good to see ya here.
You have a point there. But the real issue is not the total time recorded, but rather when the recording stops ( although I feel that 6 hours or more would be better for the long haul flights). A second consideration is the power supply. This was shown in the Swiss Air crash. The electrical failures due to the fire resulted in the failure of the ACARS, CVR and FDR. The jet hit the water a few minutes later. Finally, offline storage, like Carbonite, et al, seems a good idea. At least the investigators would have "something" to look at and analyze. Saw this with AF447, huh?
So with 370, we may have a high-quality, two hour recording of wind noise and such, and then "thump". That's if the recorder was still running.
If the data recorder was still running, then we should have data all the way back to takeoff, if I understand the current protocol for the T7. Not sure if it would have all the ECAM alerts, but need a T7 type to let us know.
Up to me, I would "demand" battery backup and a power supply that would be the last to go in an electrical fire. Fer chrissakes, my wife's iPad can run for 8 or 10 hours easily. Our dinosaur solid state recorder in the Viper ( on the ejection seat) only had a few minutes of data, but it captured several parameters of value for the accident investigation.
Leaving MA370 to one side, are there any accidents in recent times where the investigation would have significantly benefitted from more CVR time, let alone offsite storage?
So with 370, we may have a high-quality, two hour recording of wind noise and such, and then "thump". That's if the recorder was still running.
If the data recorder was still running, then we should have data all the way back to takeoff, if I understand the current protocol for the T7. Not sure if it would have all the ECAM alerts, but need a T7 type to let us know.
Up to me, I would "demand" battery backup and a power supply that would be the last to go in an electrical fire. Fer chrissakes, my wife's iPad can run for 8 or 10 hours easily. Our dinosaur solid state recorder in the Viper ( on the ejection seat) only had a few minutes of data, but it captured several parameters of value for the accident investigation.
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L-3 Aviation Recorders
Finally, offline storage, like Carbonite, et al, seems a good idea. At least the investigators would have "something" to look at and analyze.
Saw this with AF447, huh?
McLaughlin told CNN that there was no further analysis possible of the data. "Sadly this is the limit. There's no global decision even after the Air France loss [in June 2009, where it took two years to recover the plane from the sea] to make direction and distance reporting compulsory.
So it is the lack of directional and distance information that has made things difficult and they're still trying to get it mandated.
So with 370, we may have a high-quality, two hour recording of wind noise and such, and then "thump". That's if the recorder was still running.
Secondly, I'm thinking of the Helios crash where everyone on board was incapacitated by hypoxia. The CVR in that case showed that a member of the cabin crew who was training to be flight crew actually regained consciousness and tried to rescue the flight. Unfortunately he regained consciousness too late and the aircraft ran out of fuel.
Fer chrissakes, my wife's iPad can run for 8 or 10 hours easily.
Last edited by DozyWannabe; 24th Mar 2014 at 23:40.
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@ Dozy
It seems that the FAA have already mandated independent battery supplies capable of supplying 10 minutes of power
Depending on mod status of CVR, RIPS solution on Airbus A/C is additional power supply to 28vdc bus bar, this ensures that CVR,CAM and AMU are powered by A/C batteries, which are able to provide more than 10 minutes of operation.
Last edited by A33Zab; 25th Mar 2014 at 00:41.
