Announcement

Collapse
No announcement yet.

Black Box Questions for Film

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Black Box Questions for Film

    Hello all,

    I have some questions regarding the black box (namely CVR investigations of large airliners) and was hoping I could find someone who could shed some light on the specifics. Outside of what's already on Youtube and written that is.

    I'm writing a script (film) involving the recovery, and investigation of a CVR. I was hoping to find out what exactly goes on in the room where investigators listen to the CVR for the first time, what their discussions are like, and so on.

    Also details including how the recordings are transferred from the tapes in the black box to something the investigators can listen to. Is it a digital recording, does it stay on the tapes, etc.? What is it played back on? Are there ever any FBI, CIA or other intelligence/government officials in the room besides NTSB agents?

    Trying to make this as authentic as possible.

    I have some other questions as well, but if anyone can answer these or point me in the right direction that would be great. I tried contacting the NTSB directly and they responded, but after finding out it was an independent film, I didn't hear back.

    Thank you.

  • #2
    Well I can't claim to have "been there & done that" but can offer a few thoughts...

    Whether the CVR is analog or digital will likely depend on the age of the airplane, unless a newer model CVR has been retrofitted. The switch to digital recording came around 1990 so most airliners flying today have digital CVRs.

    I think also that regardless of the age of the CVR, the data will end up digital. If the CVR itself is digital that means basically reading the data out of the unit's memory chips, and possibly converting it to a PC-friendly format. If the CVR uses tape, the tape would be "played back" into a PC audio card and the audio digitized that way. In either case, the manufacturer of the CVR would most likely get involved, since they're the ones who have the equipment to access whatever's recorded in the CVR. Also of course if the CVR is damaged, their assistance would be needed.

    Once the audio resides in a digital file on a computer, it can of course be backed up and copied and I'm sure they do that. Depending on circumstances, I could see where copies of the audio file might be given to outside parties such as law enforcement agencies, or other countries' investigators in the case of an international flight.

    Regarding transcribing the audio, I get the sense it's usually a long arduous process. They don't just sit everyone in a room, play the recording from start to finish, write down what they heard, and go get a beer. They take small bits at a time, have multiple people listening, and listen repeatedly until they're either 100% sure about what was said, or 100% sure that they can't be 100% sure and then that fact is noted in the transcript. I would imagine if parts of the recording are hard to understand, digital enhancement or filtering might be applied to the recording to attempt to clean it up.

    The audio often will also be analyzed for equipment-related sounds, like the pitch or any unusual noises from the engines, sounds of controls being moved in the cockpit, warning sounds/voices and so on. I would imagine in some cases specialists might be brought in when certain sounds are deemed important.

    Re the FBI/police/etc., I would think if there's any reason whatsoever to think a criminal act may have taken place, people from law enforcement will be present when the recording is transcribed. So it would depend on the particular situation.
    Be alert! America needs more lerts.

    Eric Law

    Comment


    • #3
      If you'll be in the tape era, there are a couple of things that can be interesting to include in the movie:

      Every time the mic is keyed, it makes a sound that is recorded CVR.
      At the same time, the mic key is an event that is recorded in the FDR (flight data recorder).
      This info is used to "sync" the FDR with the CVR.

      Also, the speed of the tape cannot be controlled with 100% precision when recording. This can make that 10 minute of playback represents for example 605 seconds of recording (instead of 600). Also, the speed might be not perfectly constant, so you can have parts of the tape that were recorded slightly faster than others. But there is a way to deal with these things.

      The AC system of the plane has 400hz. The AC currents in the plane generate an electromagnetic field of 400hz. This field creates a tiny bit of "noise" that is superimposed to the recording. So the apply a narrow band-pass filter around 400hz to detect and amplify this noise and measure its exact frequency at each instant. If it's not 400hz, that portion of the tape is sped up or down so it sounds like 400hz. Then you are playing the sound back at the same speed that it was recorded.

      --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
      --- Defend what you say with arguments, not by imposing your credentials ---

      Comment


      • #4
        Originally posted by sco24 View Post
        (...)Are there ever any FBI, CIA or other intelligence/government officials in the room besides NTSB agents?

        Trying to make this as authentic as possible.
        (...)
        If you want to make this realistic, then remember that the CIA has no juridiction on the territory of the USA. They are legally (as far as I know) limited to operations abroad.

        Comment


        • #5
          Thank you for the replies everyone, very interesting. Some specific questions below.

          Whether the CVR is analog or digital will likely depend on the age of the airplane, unless a newer model CVR has been retrofitted. The switch to digital recording came around 1990 so most airliners flying today have digital CVRs.
          I'll probably be living in present day - so digital it is. But what was nice was regarding props, etc., it seemed like the older black boxes were more plentiful on the internet, sometimes at really low prices on ebay. I'll have to look around some more for new looking models (but maybe they're all the same).

          I think also that regardless of the age of the CVR, the data will end up digital. If the CVR itself is digital that means basically reading the data out of the unit's memory chips, and possibly converting it to a PC-friendly format. If the CVR uses tape, the tape would be "played back" into a PC audio card and the audio digitized that way. In either case, the manufacturer of the CVR would most likely get involved, since they're the ones who have the equipment to access whatever's recorded in the CVR. Also of course if the CVR is damaged, their assistance would be needed.
          Okay that's what I was thinking. I did read some NTSB investigators mentioning the first time they hear the CVR it's an eerie feeling (paraphrasing) because they're listening to the last minutes of people's lives. The way he said it, it gave the impression there were multiple investigators in one room, listening to the recording for the first time. And that it was controlled in this way to keep the audio recording in a controlled environment (not being passed around to different people to take home, leak to media, etc.). I'm not sure how accurate this is but it makes sense. If that's the case, I assume they're listening to it on a computer... or possibly some sort of other playback device (again just wondering for accuracy.)

          It gives me the impression it's almost like a jury... listening to it, deliberating, going over evidence. But I feel like this would strictly depend on the circumstances surrounding the crash. If there's criminal activity or not. In that same article I was reading it seemed like the FAA was the one that gave the recording to the NTSB and would take the CVR back once the investigation was complete. Then they would transcribe the audio. Does that sound accurate?

          Regarding transcribing the audio, I get the sense it's usually a long arduous process.
          That makes sense, as well as you stating they don't just sit everyone in a room.. but I would assume this comes after the investigation is complete? Or maybe this is done before/simultaneously? You'd think as investigators are deciphering clues as to what happened, they'd want to be writing it down and recording what people think is said, versus having that discussion a second time later.

          Super interesting bits of info Gabriel regarding the tape recorders. Much appreciated.

          Comment


          • #6
            Have you thought about contacting the NTSB to see if they will help you ?
            If it 'ain't broken........ Don't try to mend it !

            Comment


            • #7
              Remember what the CVR is - its a safety tool used to investigate accidents. There are very, very few occasions when a criminal investigation would be taking place immediately following an aircraft accident.

              The security of CVR/FDR data is considered most seriously, and investigating facilities are obliged to keep the data secure and private.

              There are relatively few facilities around the world that are equipped for reading and processing FDR and CVR data after an accident. Many countries will get the safety investigator of another country to do the FDR/CVR read out/analysis for them. Australia's ATSB, for example, is often requested to do analysis for neighbouring countries.

              ICAO recommend that for the read out of the data there is a representative from the country of the operator, and the FDR/CVR manufacturer present.

              ICAO also places the responsibility on the accident investigative authority of the country to do the report (which makes sense). But actual protocols for the handling of recorders etc is very much the responsibility of the country involved. So, the way the French manage data after an accident will be different to Australia, the USA, the UK etc etc.

              A good place to start is ICAO Annex 13.

              Comment


              • #8
                Have you thought about contacting the NTSB to see if they will help you ?
                Yeah I contacted them, but they seemed hesitant to speak with me after my initial questions and explanations about it being an independent film. I'll give it another try, and possibly contact the FAA and see if there's anyone who could help.

                A good place to start is ICAO Annex 13.
                Thanks for the tip, I'll check it out. Also thank you for the other info regarding who handles the investigation.

                Comment


                • #9
                  Originally posted by MCM View Post
                  Remember what the CVR is - its a safety tool used to investigate accidents.



                  There are relatively few facilities around the world that are equipped for reading and processing FDR and CVR data after an accident. Many countries will get the safety investigator of another country to do the FDR/CVR read out/analysis for them. Australia's ATSB, for example, is often requested to do analysis for neighbouring countries.

                  ICAO recommend that for the read out of the data there is a representative from the country of the operator, and the FDR/CVR manufacturer present.

                  ICAO also places the responsibility on the accident investigative authority of the country to do the report (which makes sense). But actual protocols for the handling of recorders etc is very much the responsibility of the country involved. So, the way the French manage data after an accident will be different to Australia, the USA, the UK etc etc.

                  A good place to start is ICAO Annex 13.
                  Let me try it in my own words to understand it. "ICAO places responsibility"
                  on that country in which the accident took place. Right?

                  It's a sad occasion for my contribution in your topic, so, even two and a half weeks after the catastrophe I refuse to take down my black ribbon.

                  In this case, the French BEA ( Bureau d'Enquêtes et d'Analyses pour la sécurité de l'aviation civile) does the lion part of the work. And I trust them. All of the important German TV stations report their successes.

                  And I wanna second what you've said. The German Ministry of Foreign Affairs accompanies the work,

                  and, of course, our leftseat #1, Mr Carsten Spohr.

                  PS: My home airport provides a Book of Condolence, handwritten, for all friends of EDDL. And, of course, for all those who came to the airport to fetch a friend, but nobody (exactly zero humans, incl nobody of the crew) came out of the door.

                  I was not prepared when I first saw this book and all the flowers. So I did not write into it, yesterday.
                  Last edited by LH-B744; 2015-04-11, 02:49. Reason: Book of Condolence.
                  That's what airlines are good for, amongst others,
                  The Gold Member in the 747 club, 50 years since the first LH 747.
                  And constantly advanced, 744 and 748 /w upper and lower EICAS.
                  Aviation enthusiast, since more than 35 years with home airport EDDL.

                  Comment


                  • #10
                    Why would the German Foreign Office be involved in the a plane crash investigation?

                    Comment


                    • #11
                      Yes LH-B744, the responsibility for performing an accident investigation falls to the country in which the accident occurred, providing that nation is an ICAO signatory. There are provisions in case the nation is not, or if it occurs on the high seas.

                      In the case of the recent event, the responsibility falls to the accident investigative branch of France, as you say, the BEA. In this specific case, it is more complex due to the French action of appointing a prosecutor to run an investigation. ICAO recognise that there will often be this conflicting scenario, and leave it up to individual nations to work out ways to handle this issue. Ultimately though, the BEA will produce the 'official' report.

                      There is an expectation that there will be representatives from the state of registry/operator (in this case Germany), as well as the state of the aircraft designer/manufacturer (France again).

                      This is all from an ICAO standpoint, in order to give 'rights' and 'responsibilities' to certain groups to be parties to the investigation. The investigative organisation (BEA) can use whoever they want, above and beyond these people, to assist in the completion of the report if they wish - and you would expect that to be the case. They could also invite other parties to participate to maintain political openness.

                      Comment


                      • #12
                        Originally posted by Peter Kesternich View Post
                        Why would the German Foreign Office be involved in the a plane crash investigation?
                        Short question, short answer. You obviously live in "my" German state, Northrhine-Westphalia.
                        Thus, you should know that (as I stated previously) who was the first one who transmitted the saddest of all news (in my own words):
                        "Flight 4U 9525 suffered a total loss. The 4U-A320 is broken into pieces.
                        Nobody survived." End of the quotation.

                        These are (approx) the words of our German Minister of Foreign Affairs,
                        Mr Frank Walter Steinmeier.

                        PS: Mr Steinmeier was on site, in France.
                        Last edited by LH-B744; 2015-04-11, 03:34. Reason: Minister on site
                        That's what airlines are good for, amongst others,
                        The Gold Member in the 747 club, 50 years since the first LH 747.
                        And constantly advanced, 744 and 748 /w upper and lower EICAS.
                        Aviation enthusiast, since more than 35 years with home airport EDDL.

                        Comment


                        • #13
                          Originally posted by LH-B744 View Post
                          Short question, short answer. You obviously live in "my" German state, Northrhine-Westphalia.
                          Thus, you should know that (as I stated previously) who was the first one who transmitted the saddest of all news (in my own words):
                          "Flight 4U 9525 suffered a total loss. The 4U-A320 is broken into pieces.
                          Nobody survived." End of the quotation.

                          These are (approx) the words of our German Minister of Foreign Affairs,
                          Mr Frank Walter Steinmeier.

                          PS: Mr Steinmeier was on site, in France.
                          Just because a politician informs about or comments on an event does not mean he is involved. The German Government agency working with the BEA to determine what happened is not the Foreign Office but the Luftfahrtbundesamt (LBU), or more precisely the Bundesstelle für Flugunfalluntersuchung (BFU).

                          But this thread is drifting off-topic...

                          Comment

                          Working...
                          X