6 ms·

Unfortunately even if this is the case (and color me skeptical given the sheer volume of media misinformation that this story has generated), the cockpit voice

by grej 13y ago

Unfortunately even if this is the case (and color me skeptical given the sheer volume of media misinformation that this story has generated), the cockpit voice recorder only records the last two hours of data, so regrettably we may never know what happened in those moments when the flight was diverted, even if the wreckage is found and the black box is salvageable. EDIT - Clarification that the cockpit voice recorder (not flight data recorder) only captures the last two hours. Source: http://en.wikipedia.org/wiki/Cockpit_voice_recorder http://en.wikipedia.org/wiki/Cockpit_voice_recorder

ekianjo 13y ago
We may be able to understand what happened through the last 2 hours of data though. If there's pure silence in the cockpit we could infer a number of things about what occured, plus the debris would give additional information as well.
AlexMuir 13y ago
I believe the Cockpit Voice Recorder (CVR) only keeps two hours, but the Flight Data Recorder (FDR) records for considerably longer. Both make up a black box. It will certainly be far more difficult to establish what happened without voice recordings though.
- Eliezer 13y ago
  I guess they try to keep the airplanes cheap enough that they can't spring for a 16gb card in the CVR.
  - marshray 13y ago
    If you think the rule about turning off your electronics during takeoff and landing is conservative, try to imagine what it would take to certify a solid-state memory card for use in that application.
    - 001sky 13y ago
      Why would doubling or quadrupuling the storage be a problem? Assuming you have the cost of a new chip paid for, I dont see the capacity issue. Or are you saying solid state is incompatible with the engineering parameters of a black box altogether? In that case, the answer is even simpler: just add more of what's already in there.
      - mpyne 13y ago
        That's the point, it's not simply a capacity issue. They could plug in a $10 SD card that comes pre-installed to a Nintendo DS and solve the capacity issue. Rather, it's a certification issue, and the certification process itself is so expensive that you don't simply upgrade every black box every 4 years as storage gets cheaper.
        ams6110 13y ago
        There's also a pilots union issue, they don't want every offhand utterance, gripes about management, gossip, etc. preserved for eternity.
        001sky 13y ago
        This sounds more likely the real answer.
        ddeck 13y ago
        This is correct. Looking at the most recent FAA CVR reg. revision in 2008, which increased the required duration to 2 hours: "Revisions to Cockpit Voice Recorder and Digital Flight Data Recorder Regulations" [1] The FAA proposed that all CVRs be able to retain the last two hours of cockpit audio. Both the NTSB and the Transportation Safety Board of Canada noted that the short duration of available cockpit audio hindered the investigation of several accidents. The Air Line Pilots Association (ALPA) did not support the proposal to increase CVR recording time because the FAA did not propose any increase in the privacy protections regarding the access and use of information recorded on a CVR. The ALPA stated that existing protections are inadequate despite years of its attempts to change the standard. [1] http://www.gpo.gov/fdsys/pkg/FR-2008-03-07/pdf/E8-3949.pdf http://www.gpo.gov/fdsys/pkg/FR-2008-03-07/pdf/E8-3949.pdf
  - ekianjo 13y ago
    yeah i'm sure you 16gb SD card data is made to survive several hundred Gs collision crash. EDIT : adjusted Gs
    - anigbrowl 13y ago
      It doesn't matter that much whether it does or not. Modern data storage is so cheap that we could stick in 8 of them in addition to the super-touch CVR at very little extra cost, and odds are that one of the cheapie units would survive. The hardened CVR system is great, but it should be a last resort sort of thing. We can have cheap, redundant, and high-capacity systems in addition to the CVR for peanuts, so why don't we?
    - Symmetry 13y ago
      Actually a small device with no internal moving parts will take 50Gs no problem, 1000s of Gs if you have some decent potting. It's keeping some sort of power source active through a high G crash that's the challenge.
    - chaz 13y ago
      SwissAir 111 impacted at an estimated 350g.
      - vacri 13y ago
        The sudden stop at the end of a fall is routinely that high. If you look at warranties for spinning disc hard drives, they'll be rated for several hundred G during transit. Sounds silly, but it's the difference between landing on a surface with give, like carpet, or landing on an unforgiving surface like concrete.
deleted 13y ago
[deleted]
haberman 13y ago
Source? I know nothing about this, but Wikipedia says: "Most FDRs record approximately 17–25 hours worth of data in a continuous loop." http://en.wikipedia.org/wiki/Flight_data_recorder#Design http://en.wikipedia.org/wiki/Flight_data_recorder#Design EDIT: ah, it looks like you are talking about the cockpit voice recorder, which records 2 hours of data: http://en.wikipedia.org/wiki/Cockpit_voice_recorder http://en.wikipedia.org/wiki/Cockpit_voice_recorder
- grej 13y ago
  Several sources, here's one: http://www.washingtonpost.com/local/trafficandcommuting/malaysia-airlines-flight-recorder-beacons-send-signal-for-30-days-before-batteries-die/2014/03/11/1d1cb3d8-a8a2-11e3-b61e-8051b8b52d06_story.html http://www.washingtonpost.com/local/trafficandcommuting/mala... Yeah - sorry I should have clarified voice recorder not the flight data recorder. Will edit.
daturkel 13y ago
I think you're thinking of the cockpit voice recorder [0], the flight data recorder [1] (also referred to as the black box) contains all sorts of data about what commands were sent to plane and, Wikipedia says, records "17–25 hours worth of data in a continuous loop" (presumably overwriting the oldest data once it's reached capacity). [0] https://en.wikipedia.org/wiki/Cockpit_voice_recorder https://en.wikipedia.org/wiki/Cockpit_voice_recorder [1] https://en.wikipedia.org/wiki/Flight_Data_Recorder https://en.wikipedia.org/wiki/Flight_Data_Recorder edit: just about everyone's beat me to it!
pasbesoin 13y ago
I'm not sure what the current physical medium / technology is, but with some generations, IIRC forensics could actually recover several of the most recent recording passes over the medium that travelled in a closed loop -- if there were enough incentive and resources to do so.
nerfhammer 13y ago
We could learn quite a bit, for instance, if the voices on the recorder were neither of the flight crew, or whatever the subject of what was said could suggest whatever had happened at the diversion ... unless whoever was smart enough to disable the transponders would disable the cabin mic, which would probably be the least informative condition
downandout 13y ago
The CVR only recording two hours is absolutely inexcusable. Why does my iPhone - $850 retail - have capabilities that far surpass those of a $250 million modern passenger jet? Hopefully after this incident, public outrage over these ridiculous technological shortcomings will be the catalyst for legislation. Throwing in some extra satellite transmission, GPS, and voice recording capabilities that will hold up even in the event of an electrical issue or fire, and that cannot be disabled by bad actors, just cannot be this difficult. In my view, the moment this plane went off course, or a fire alarm went off or any other irregularity occurred, a Malaysian Airlines control center should have been alerted and been able to bring up video of the cockpit, maybe the passenger cabin as well, and been able to remotely view diagnostic and positioning data. All of this could easily and cheaply occur via a satellite internet connection. Edit: For the record, I am not suggesting that plugging a commercial iPhone into a cockpit would work - I'm comparing the capabilities of consumer technology to cockpit technology, which seems woefully inadequate to me.
- learc83 13y ago
  >Why does my iPhone - $850 retail - have capabilities that far surpass those of a $250 million modern passenger jet? Because your iPhone isn't designed to survive a plane crash. The requirements for both design and certification are so different that comparisons to consumer electronics (especially regarding price) are meaningless.
  - downandout 13y ago
    So the thought that it might be possible to install some more memory on the CVR is completely outrageous?
  - kenrikm 13y ago
    While correct. I for one don't see a reason they could not supplement the highly fault tolerant Cockpit Voice Recorder with a backup system that can record longer periods of time. worst case you only get the two hours.
    - 13y ago
weaksauce 13y ago
Does the voice recorder still function if they pull all the fuses? It's possible, if that's the case, that they will get the lead up to the event on voice recorder. seems like planes have redundancy though and this particular system is probably on a different power supply.

by grej 13y ago

ekianjo 13y ago

We may be able to understand what happened through the last 2 hours of data though. If there's pure silence in the cockpit we could infer a number of things about what occured, plus the debris would give additional information as well.

AlexMuir 13y ago

I believe the Cockpit Voice Recorder (CVR) only keeps two hours, but the Flight Data Recorder (FDR) records for considerably longer. Both make up a black box. It will certainly be far more difficult to establish what happened without voice recordings though.

Eliezer 13y ago
I guess they try to keep the airplanes cheap enough that they can't spring for a 16gb card in the CVR.
- marshray 13y ago
  If you think the rule about turning off your electronics during takeoff and landing is conservative, try to imagine what it would take to certify a solid-state memory card for use in that application.
  - 001sky 13y ago
    Why would doubling or quadrupuling the storage be a problem? Assuming you have the cost of a new chip paid for, I dont see the capacity issue. Or are you saying solid state is incompatible with the engineering parameters of a black box altogether? In that case, the answer is even simpler: just add more of what's already in there.
    - mpyne 13y ago
      That's the point, it's not simply a capacity issue. They could plug in a $10 SD card that comes pre-installed to a Nintendo DS and solve the capacity issue. Rather, it's a certification issue, and the certification process itself is so expensive that you don't simply upgrade every black box every 4 years as storage gets cheaper.
      - ams6110 13y ago
        There's also a pilots union issue, they don't want every offhand utterance, gripes about management, gossip, etc. preserved for eternity.
        001sky 13y ago
        This sounds more likely the real answer.
        ddeck 13y ago
        This is correct. Looking at the most recent FAA CVR reg. revision in 2008, which increased the required duration to 2 hours: "Revisions to Cockpit Voice Recorder and Digital Flight Data Recorder Regulations" [1] The FAA proposed that all CVRs be able to retain the last two hours of cockpit audio. Both the NTSB and the Transportation Safety Board of Canada noted that the short duration of available cockpit audio hindered the investigation of several accidents. The Air Line Pilots Association (ALPA) did not support the proposal to increase CVR recording time because the FAA did not propose any increase in the privacy protections regarding the access and use of information recorded on a CVR. The ALPA stated that existing protections are inadequate despite years of its attempts to change the standard. [1] http://www.gpo.gov/fdsys/pkg/FR-2008-03-07/pdf/E8-3949.pdf http://www.gpo.gov/fdsys/pkg/FR-2008-03-07/pdf/E8-3949.pdf
- ekianjo 13y ago
  yeah i'm sure you 16gb SD card data is made to survive several hundred Gs collision crash. EDIT : adjusted Gs
  - anigbrowl 13y ago
    It doesn't matter that much whether it does or not. Modern data storage is so cheap that we could stick in 8 of them in addition to the super-touch CVR at very little extra cost, and odds are that one of the cheapie units would survive. The hardened CVR system is great, but it should be a last resort sort of thing. We can have cheap, redundant, and high-capacity systems in addition to the CVR for peanuts, so why don't we?
  - Symmetry 13y ago
    Actually a small device with no internal moving parts will take 50Gs no problem, 1000s of Gs if you have some decent potting. It's keeping some sort of power source active through a high G crash that's the challenge.
  - chaz 13y ago
    SwissAir 111 impacted at an estimated 350g.
    - vacri 13y ago
      The sudden stop at the end of a fall is routinely that high. If you look at warranties for spinning disc hard drives, they'll be rated for several hundred G during transit. Sounds silly, but it's the difference between landing on a surface with give, like carpet, or landing on an unforgiving surface like concrete.

deleted 13y ago

[deleted]

haberman 13y ago

Source? I know nothing about this, but Wikipedia says: "Most FDRs record approximately 17–25 hours worth of data in a continuous loop." http://en.wikipedia.org/wiki/Flight_data_recorder#Design http://en.wikipedia.org/wiki/Flight_data_recorder#Design EDIT: ah, it looks like you are talking about the cockpit voice recorder, which records 2 hours of data: http://en.wikipedia.org/wiki/Cockpit_voice_recorder http://en.wikipedia.org/wiki/Cockpit_voice_recorder

grej 13y ago
Several sources, here's one: http://www.washingtonpost.com/local/trafficandcommuting/malaysia-airlines-flight-recorder-beacons-send-signal-for-30-days-before-batteries-die/2014/03/11/1d1cb3d8-a8a2-11e3-b61e-8051b8b52d06_story.html http://www.washingtonpost.com/local/trafficandcommuting/mala... Yeah - sorry I should have clarified voice recorder not the flight data recorder. Will edit.

daturkel 13y ago

I think you're thinking of the cockpit voice recorder [0], the flight data recorder [1] (also referred to as the black box) contains all sorts of data about what commands were sent to plane and, Wikipedia says, records "17–25 hours worth of data in a continuous loop" (presumably overwriting the oldest data once it's reached capacity). [0] https://en.wikipedia.org/wiki/Cockpit_voice_recorder https://en.wikipedia.org/wiki/Cockpit_voice_recorder [1] https://en.wikipedia.org/wiki/Flight_Data_Recorder https://en.wikipedia.org/wiki/Flight_Data_Recorder edit: just about everyone's beat me to it!

pasbesoin 13y ago

I'm not sure what the current physical medium / technology is, but with some generations, IIRC forensics could actually recover several of the most recent recording passes over the medium that travelled in a closed loop -- if there were enough incentive and resources to do so.

nerfhammer 13y ago

We could learn quite a bit, for instance, if the voices on the recorder were neither of the flight crew, or whatever the subject of what was said could suggest whatever had happened at the diversion ... unless whoever was smart enough to disable the transponders would disable the cabin mic, which would probably be the least informative condition

downandout 13y ago

The CVR only recording two hours is absolutely inexcusable. Why does my iPhone - $850 retail - have capabilities that far surpass those of a $250 million modern passenger jet? Hopefully after this incident, public outrage over these ridiculous technological shortcomings will be the catalyst for legislation. Throwing in some extra satellite transmission, GPS, and voice recording capabilities that will hold up even in the event of an electrical issue or fire, and that cannot be disabled by bad actors, just cannot be this difficult. In my view, the moment this plane went off course, or a fire alarm went off or any other irregularity occurred, a Malaysian Airlines control center should have been alerted and been able to bring up video of the cockpit, maybe the passenger cabin as well, and been able to remotely view diagnostic and positioning data. All of this could easily and cheaply occur via a satellite internet connection. Edit: For the record, I am not suggesting that plugging a commercial iPhone into a cockpit would work - I'm comparing the capabilities of consumer technology to cockpit technology, which seems woefully inadequate to me.

learc83 13y ago
>Why does my iPhone - $850 retail - have capabilities that far surpass those of a $250 million modern passenger jet? Because your iPhone isn't designed to survive a plane crash. The requirements for both design and certification are so different that comparisons to consumer electronics (especially regarding price) are meaningless.
- downandout 13y ago
  So the thought that it might be possible to install some more memory on the CVR is completely outrageous?
- kenrikm 13y ago
  While correct. I for one don't see a reason they could not supplement the highly fault tolerant Cockpit Voice Recorder with a backup system that can record longer periods of time. worst case you only get the two hours.
  - 13y ago

weaksauce 13y ago

Does the voice recorder still function if they pull all the fuses? It's possible, if that's the case, that they will get the lead up to the event on voice recorder. seems like planes have redundancy though and this particular system is probably on a different power supply.