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NTSB Wants PDF Removed After It Exposed Final Cockpit Audio From UPS Crash (cnn.com) 65

The NTSB temporarily closed public access to nearly all investigation dockets after people used a spectrogram image from a PDF in the UPS flight 2976 crash file to reconstruct approximate cockpit voice recorder audio and post it online. "We show our work and we've been doing this type of thing for years. Nobody was aware that you can recreate audio from a picture," a spokesperson for the board said. "NTSB is looking to make sure there's nothing else in the docket that could compromise anybody's privacy... now that we understand the possibility of a digital recreation." CNN reports: Cockpit voice recordings, often referred to as the CVR, capture everything commercial pilots say and are valuable during NTSB investigations, but are almost never released out of respect for the victims and their families. UPS flight 2976 crashed on November 4, when an engine separated from the wing while it was taking off from Louisville, Kentucky. The three crew members onboard were killed along with 12 people on the ground. During a two-day investigative hearing this week, the board released a docket full of details about the crash. Besides thousands of pages of reports and video showing the engine separating, it included a transcript of the CVR and a PDF file showing an analysis of the spectrogram of the audio it recorded.

A spectrogram is a still image that is a visual representation of the audio, showing the ups and downs of the frequencies. Using that still image, members of the public were able to recreate the voices of the pilots in the moments before the plane crashed and post the results online. The clip, which included background noise and echoes, covered the last 30 seconds of the flight as the pilots struggled with the disabled aircraft as well as recordings of testing the NTSB did on another aircraft.

In a statement on Thursday, the board made clear it "does not release cockpit voice recordings" due to federal law and because of the highly sensitive nature of what they include, but it was "aware that advances in image recognition and computational methods have enabled individuals to reconstruct approximations of cockpit voice recorder audio from sound spectrum imagery." Investigation dockets are made public for transparency, but this week, the board took the rare step of closing public access to all dockets, including the one for the UPS crash. [...] The NTSB is urging platforms like X and Reddit to remove posts with the audio.

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NTSB Wants PDF Removed After It Exposed Final Cockpit Audio From UPS Crash

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  • Wonder if anyone grabbed old crash data and is running analysis for us now.

    • Not sure what you hope to gain from this. For the most part where audio was captured complete transcripts were released. In this case too.

  • The NTSB is urging platforms like X and Reddit to remove posts with the audio.

    Yes, that should work. Barbara, what do you think?

  • Like . . come on.

  • Hmmm. (Score:4, Interesting)

    by jd ( 1658 ) <imipak@yaho[ ]om ['o.c' in gap]> on Friday May 22, 2026 @05:58PM (#66156418) Homepage Journal

    A spectrogram is basically a description of the sound and Daphne Oram pioneered technology for turning the informational sections of a spectrogram into sound back in 1958. That would be.... 68 years ago, by my reckoning.

    Now, technology has moved on a great deal in 68 years. Exactly what you could do today, relative to what she did back then, is obviously significant. But this really should not have come as a shock.

    The lack of understanding of this sort of stuff shows what happens when you have too many niche specialists and too few people who understand the broad technology.

    • by ceoyoyo ( 59147 )

      It wasn't a spectrogram though. It was a picture of a spectrogram. I haven't had a chance to watch Scott Manley's video yet, but unless somebody screwed up and embedded the actual spectrogram, or maybe an unreasonably high resolution image of it, it is pretty impressive to reconstruct 30 seconds of recognizable audio from what should have been a random JPEG figure in a PDF.

      • by jd ( 1658 )

        Daphne Oram's Oramics machine turned hand-drawn squiggles that were the information-bearing portions of a spectrogram into recognisable audio. And, like I said, that was 1958. A spectrogram, as others have noted, is an image.

    • The lack of understanding of this sort of stuff shows what happens when you have too many niche specialists and too few people who understand the broad technology.

      I don't think anyone didn't understand this, I think they didn't thing it mattered until someone actually proved the edge case. Heck maybe it still doesn't matter. It could very well be that a lawyer had a look at the wording of the law and changed their mind and that reconstructed audio counted.

      If you spend your life analysing every single edge case that may happen you'll never get anything done. It's not a question of understanding, it's just a question of when near enough is good enough to move on, and h

      • by jd ( 1658 )

        If you had specialists do so, I'd agree.

        This is why programmers do not check every corner case, they hire QA enginers to check every corner case.

        You hire generalists to see how interactions between technologies impact things.

    • Dude, a spectrogram is just a rendered version of an FFT, and the "technology" for converting it back to audio is just an inverse FFT.

      For that matter trained linguists can often read speech directly from spectrograms - you just need to recognize the formants, and there are other obvious clues such as fricatives (burst of high frequency noise), plosives (sudden onsets of speech energy from closed lips to open), etc.

      • by jd ( 1658 )

        Yes, that's perfectly obvious. If you check the Oramics machine from 1958, that's basically what it was.

        • Yeah, but you said:

          > Daphne Oram pioneered technology for turning the informational sections of a spectrogram into sound back in 1958

          You seem to want to make it sound like some discovery rather than just IFFT or just "add the sine waves back together". For sure what's trivial to do on a modern computer would have been more of a challenge using 1958 tech, but that's because of the tech, not because of the problem requiring some breakthrough "technology".

          You also said "A spectrogram is basically a descript

          • by jd ( 1658 )

            FFT didn't exist for another decade.

            • Sure, although the Fourier transform itself dates back to 1822.

              Of course all you need to create a spectrogram is a filterbank - a bunch of analog filters, and all you need to invert it is to add the frequency amplitudes back together.

              This is all a bit irrelevant though since what Oram built was actually an analog musical synthesizer controlled by hand drawn (then optically scanned) film strips. No spectrogram involved at all. Similar analog scanning tech COULD have been used to scan a spectrogram and contro

  • Please sar remove the audio spectograph sar it's very important sar

  • by PPH ( 736903 ) on Friday May 22, 2026 @08:01PM (#66156598)

    ... was a spectogram published in the report PDF? What value would that add beyond transcribed audio with time stamps?

    On the other hand, when I worked for Boeing, we would produce thick certification documents chock full data of questionable value. To impress the FAA, I suppose. And to keep them from actually bothering to read the interesting bits.

  • by BoogieChile ( 517082 ) on Saturday May 23, 2026 @12:09AM (#66156756)
    > "Nobody was aware that you can recreate audio from a picture," a spokesperson for the board said.

    "Nobody ever before in the history of the world..."

    Well, since about 2008, at least, anyway -> https://arss.sourceforge.net/e... [sourceforge.net]
    • I will assume that these organizations don't have any engineers. Just about every single one should be familiar with an FFT.
  • by belmolis ( 702863 ) on Saturday May 23, 2026 @03:15AM (#66156822) Homepage
    The ability to convert a spectrogram to sound has long been known in the speech research community. In 1950 a device known as the Pattern Playback was built at Haskins Laboratories. You would draw an artificial spectrogram and feed it to the machine and it would play back the corresponding sound. It was used to perform experiments on the acoustic cues for speech perception. The original machine was last used for research in 1976. See the Wikipedia article: https://en.wikipedia.org/wiki/... [wikipedia.org]
    • This isn't some hi-tech research secret. A spectrogram is just a rendered version of an FFT, so it's gob-smackingly obvious you can convert it back to audio.

  • """Nobody was aware that you can recreate audio from a picture," a spokesperson for the board said. " """ - OUCH! Doesn't instill much confidence in their competence. Should be bleedingly obvious that the image of a spectrogram has got all the information needed ...

  • by unami ( 1042872 ) on Saturday May 23, 2026 @07:37AM (#66156960)
    You can show the audio in a visual representation, but then it's surprising that the visual tepresentation can be turned into audio again? How in the world could anyone with any capability for logical thought "not be aware" of this? o wobder if they've ever heard of something like a radio.
  • What tool was used for this "reverse engineering"?

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