The CVR's speed didn't match the ATC recording or the BTC2937 CVR, so I resampled the audio to be a bit faster in order to compensate. Useful if you want to sync this up perfectly. The way I accomplished this was by using Adobe Audition's frequency analysis tool to analyze the beeps in the CVR and the ATC audio. The ATC audio has an average peak frequency of 851Hz for the beeps, but the CVR had a peak of 806Hz. So, I sped up the CVR by the following amount, and then verified after that the frequencies matched:
The CVR's speed didn't match the ATC recording or the BTC2937 CVR, so I resampled the audio to be a bit faster in order to compensate. Useful if you want to sync this up perfectly. The way I accomplished this was by using Adobe Audition's frequency analysis tool to analyze the beeps in the CVR and the ATC audio. The ATC audio has an average peak frequency of 851Hz for the beeps, but the CVR had a peak of 806Hz. So, I sped up the CVR by the following amount, and then verified after that the frequencies matched:
0:00 CVR Starts 0:05 Background noise 0:18 Pilots talking 0:22 Background Noise 0:40 TCAS Descent Transmission 0:45 Descend! Fuck, me. Descend hard... 0:51 Collision 1:00 End of recordingComair Flight 3272 Cockpit Audio and Animation #aviation #cvr #plane #crashJerald Heiss2023-09-23 | 29 occupants, 0 survivors January 9, 1997 Embrar EMB-120
Captain: Dann Carlsen, age 42 First Officer: Kenneth Reece, age 29 (Pilot Flying)
"The NTSB determined that the probable cause was inadequate standards for icing operations while in flight, specifically the failure of the Federal Aviation Administration to establish adequate minimum airspeeds for icing conditions, leading to a loss of control when the airplane accumulated a thin, rough accretion of ice on its lifting surfaces.
A contributing factor was the crew's decision to operate in icing conditions while near the lower end of the flight envelope while the flaps were retracted. Comair had not established unambiguous minimum airspeed values for flap configurations and for flight in icing conditions. They also, against recommendation of the plane's manufacturer, failed to activate the deicing boots on the wings. This was because the Comair Flight manual recommendation was in contravention of the manufacturers due to a concern over "ice bridging", a concern held over from older planes that was no longer valid on newer generation planes like the Embraer 120. "Comair Flight 5191 CVR & Crash Animation (Enhanced Audio)Jerald Heiss2023-09-11 | ...#shorts Northwest 255 Crash animation and CVR/black box audio, NW Flight 255, August 16 1987Jerald Heiss2023-08-21 | ...Northwest 255 CVR - Sound Spectrum ViewJerald Heiss2023-08-14 | Using spectral analysis, frequency analysis, and a spectrograph/spectrogramNorthwest 255 CVR - Proof there was a Stall voice overlapping the Ah exclamation (see chapters)Jerald Heiss2023-08-14 | See chapters for explanation. this is an unedited video so it doesn't really do a good job of explaining things itself, this was just a quick and dirty demonstration because I keep seeing questions about it and I wanted to provide objective evidence.
Playing around in Adobe Audition to show how the stall voice can be separated and isolated from that part, and also how it can be enhanced to demonstrate better how it's actually present, overlapping the "Ah!".
Explanation:
0:00 Start 0:09 Original Sound 0:42 Side by side "Stall" and "Ah" comparison 1:07 Slicing out the "Stall" sound 1:52 Edited Sound - "Stall" voice removed 2:24 Isolated "Stall" sound 3:01 Enhanced "Stall" sound overlap 3:13 2x Enhanced "Stall" sound overlap 3:26 3x Enhanced "Stall" sound overlap 4:16 Isolated "Stall" side by side with Edited Sound 4:37 Original Sound AgainNW 255 FDR animation + CVR, Full Long Uncensored Version, forensic animation, enhanced audioJerald Heiss2023-08-11 | Northwest 255 FDR + CVR, Full Long Uncensored VersionNorthwest 255 Uncensored Extended CVR Plus new animation. Very high quality.Jerald Heiss2023-08-08 | This is a teaser; it's only a small portion of what was found. @alexhoe02 did the full upload: youtube.com/watch?v=bmhMmVxk3qY
This is a previously unheard *(On YouTube) version and portion of the CVR of Northwest Flight 255.
00:00 Start of takeoff clearance 00:16 Takeoff Roll Starts 00:41 100 Knots 00:53 V1, Rotate 01:00 Stick Shaker Activation Audible 01:15 First ImpactAerocaribe 7831 CVR denoised + FDRJerald Heiss2023-08-07 | ...MD-80, MD-82 Stall Warning (Both Voices), DC-9, DC-10Jerald Heiss2023-07-29 | Thanks to @TheAmazingJimbo for the source. Related to Northwest NW 255.
DC-9-82 SSRS, Supplemental Stall Recognition System
Activates when the stall angle of attack _has been reached_ and there is *no more safety margin*.
The stall warning remains active until the stall condition no longer exists.
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The reason for the notability of this video is that this is how a stall warning is supposed to sound in this aircraft when all the circuit breakers are active. but if the p-47 circuit breaker is disabled, which disables the takeoff configuration warning system, it also disables the higher pitched stall voice and higher pitched stall warning tone.CVR + Animation 2004 King Air Macedonia Crash, English CC, Enhanced AudioJerald Heiss2023-05-20 | ...TAROM Flight 381: Enhanced CVR, FDR, Captions, TranslationJerald Heiss2023-05-02 | For more info on this near crash, see this amazing and comprehensive video on the subject: youtube.com/watch?v=wlYbpgpciTA
the translation was done by copying each line of the transcript from the PDF file of the French incident report into a spreadsheet, and then I used GPT-4 to generate code which turned that into subtitles, which was hard because all of the different sound sources were each in their own columns. And then I used GPT-4 to translate the subtitles into English. And then I asked a family member with a Romanian fiance if they could help, and their mother ended up suggesting a couple of changes. The original transcript was in French which had been translated from Romanian.Spanair 5022 CVR + ATC + Subtítulos + Audio mejoradoJerald Heiss2023-04-01 | 03:28 Audio con ruido eliminado(Outdated, see description) Northwest 255 FDR Animation + CVR (Enhanced HQ Audio)Jerald Heiss2023-03-13 | Newer, much longer CVR: youtu.be/noADOBnvfZQ
CVR of the 1987 Northwest 255 crash, synced to an animation [CC]. Audio and video is a rarely heard high quality version of the cockpit recording from the documentary Why Planes Go Down (1996). Audio has been edited to remove noise.(Outdated, see description) Northwest 255 FDR Animation + CVR (new HQ audio)Jerald Heiss2023-03-12 | Newer, much longer CVR: youtu.be/noADOBnvfZQ
CVR of the 1987 Northwest 255 crash, synced to an animation [CC]. Audio and video is a rarely heard high quality version of the cockpit recording from the documentary Why Planes Go Down (1996).(Outdated, see description) Northwest 255 CVR High Quality (Enhanced)Jerald Heiss2023-03-12 | Newer, much longer CVR: youtu.be/noADOBnvfZQ
Denoised(Outdated, see description) Northwest 255 CVR High QualityJerald Heiss2023-03-12 | Newer, much longer CVR: youtu.be/noADOBnvfZQ
From the documentary Why Planes Go Down (1996) with Gillian Anderson
NW255CVR - BTC 2937 - Denoised and EnhancedJerald Heiss2023-02-24 | WAV download drive.google.com/file/d/1lbnG0IDmw32-Qcn308ksRfRnmxeqETZX/view?usp=sharingCVR - Western 2605 (Enhanced, Corrected Speed)Jerald Heiss2023-02-24 | ...ATC - Northwest 255 (Enhanced Audio)Jerald Heiss2023-02-23 | WAV file link drive.google.com/file/d/1lkygB4ht6h_JKGHfM7raEhSaJXr2UM2e/view?usp=sharing(Outdated, see description) CVR - Northwest 255 (Enhanced)Jerald Heiss2023-02-23 | Newer, much longer CVR: youtu.be/noADOBnvfZQNorthwest 255 CVR audio compared to ATC audio - I can hear no Im so sorry or brace in the CVRJerald Heiss2023-02-12 | There are videos going around with seemingly incorrect captions. People like @SongJLikes are perpetuating this baseless purported misinformation. The only words in the NTSB transcript after the final stall horn are just the words of the helicopter transmission that was made over the ATC frequency:
20:45:18 102UM (to Detroit tower) Metro tower lifeguard copter one zero two Uniform Mike is ah..
So, what I'm saying is that the CVR audio is real, as well as the ATC audio, but the captions going around on some videos are incorrect. because what you're hearing in the CVR audio is clearly just the same audio from the ATC recording as well, at the exact same time stamp.CVR - East Coast Jet Flight 81 (headset audio only) [CC]Jerald Heiss2022-06-21 | I removed the center channel, then combined what was left into one channel (there's not really good separation between the mics unfortunately)CVR- East Coast Jet Flight 81 (CAM only)Jerald Heiss2022-06-21 | I extracted the center channel to try to get just the CAM. It worked okay.Western Airlines 2605 CVR, Much Clearer Vocals, with Actually Accurate Captions (Denoised) [CC]Jerald Heiss2022-06-21 | I denoised the CVR so you can hear the voices better. Apparently the official transcript is not quite correct so I'll put my interpretation in the captions. Let me know if you think I got anything wrong or missed something.DHL 611 CVR, repeated at slower and slower speedsJerald Heiss2022-04-10 | ...DHL 611, isolated vocalsJerald Heiss2022-03-08 | I edited it down to just the parts with talking; the timing is of course not the same as the original. Isolated via lalal.aiBTC 2937 CVR, New Full Version, Completely newly Isolated, 100% lossless quality, uncutJerald Heiss2022-02-24 | Improved version of: youtube.com/watch?v=xTV8cknEu18 WAV Version: drive.google.com/file/d/1-Cxz3B7VzKBZusDSgANybV7M0pAKwA4S/view?usp=sharing
0:00 Start 4:44 TCAS Traffic Alert 4:58 TCAS: "Climb" 5:08 Radio: "Expdedite descent, level 350, BTC 2937" 5:21 Radio: "Dilmun 600 ah...TCAS Descent" 5:34 Impact 6:04 Pilots' vocalizationsÜberlingen Air Disaster 2002: Realtime Animation + CVRs + ATC (Animation by Michael Fang)Jerald Heiss2022-02-22 | Note: The timing of the DHL CVR transcript is wrong in the animation Note 2: There is more BTC2937 CVR audio but I cut it off at the end of the animation (Audio Source: youtube.com/watch?v=_jFtxQMEmP0)
Animation Credit: Michael Fang (youtube.com/watch?v=ksyv5Z0lsFg)Synced CVRs and ATC audio, Überlingen Air Disaster 2002, BTC2937 + DHL611 + ATC (Corrected volume)Jerald Heiss2022-02-17 | (re-upload; the ATC audio isn't so loud in this one) The DHL 611 audio turned out to be slowed down compared to the ATC audio and the BTC 2937 audio, so I had to speed it up. Left channel: BTC2937 + ATC Right channel: DHL611 + ATC
When editing this I realized that the crew of BTC 2937 started making noises only after the controller (Peter Nielsen) called them after the crash. Maybe they were woken up by his voice?Synced DHL611 CVR + ATC audio, Überlingen Air Disaster 2002Jerald Heiss2022-02-16 | Left Channel: DHL 611 CVR (starts at 1:36) Right Channel: ATC Audio
Not featured: BTC 2937 AudioSynced CVRs, Überlingen Air Disaster 2002, BTC2937 + DHL611Jerald Heiss2022-02-16 | Left Channel: BTC2937 Right Channel: DHL611Synced BTC2937 CVR + ATC audio, Überlingen Air Disaster 2002Jerald Heiss2022-02-16 | Left Channel: BTC2937 CVR Right Channel: ATCCVR - BTC 2937 [CC] (isolated) (captions start at 2:48)Jerald Heiss2022-01-12 | Feel free to upload to your own channel. Download the .WAV here: drive.google.com/file/d/1eidPExQr_mgaG1Ao4ufHQSgDDOsZ9Dcu/view?usp=sharing
Captions based on the transcript in this PDF here: http://www.bfu-web.de/EN/Publications/Investigation%20Report/2002/Report_02_AX001-1-2_Ueberlingen_Appendix_1-3.pdf?__blob=publicationFile
The captions in that transcript only start halfway into this video, because I didn't have another transcript available. If you know of a more thorough transcript please share it with me so I can add the captions to this video.
00:00 CVR starts 02:48 Captioned section 02:59 TCAS "TRAFFIC" 03:15 TCAS: "CLIMB" 03:37 DHL: "TCAS Descent" 03:50 ImpactCVR - DHL 611, Isolated [CC] (100% perfect lossless quality)Jerald Heiss2022-01-12 | *Note: for an unknown reason, this recording is slightly slowed down compared to the official ATC audio and the BTC2937 audio*
If you do upload this, I recommend using MKVToolNix, or some other program, to put the .wav audio straight into a .mkv file, so that when it's uploaded to YouTube, the audio is only compressed one time.
Captions based on the transcript in this PDF here: http://www.bfu-web.de/EN/Publications/Investigation%20Report/2002/Report_02_AX001-1-2_Ueberlingen_Appendix_1-3.pdf?__blob=publicationFile
This is not in realtime; it's several fragments of the CVR pieced together. See the PDF I linked for the real timeline of events.
*How I did it:* I panned the audio channels from that animation so that the BTC2937 audio was in the exact center, then I cancelled out the left and right channels, leaving only the DHL611 audio. The original .avi file had PCM audio, meaning this was a completely lossless process, unlike my previous version.
*More detailed description of how:* I used Adobe Audition, but any audio editing program would have worked; I used the pan/expand tool to dynamically pan the audio, such that the BTC audio was in the exact center channel. I figured out the exact amount to pan it by by using the stereo phase spectrum viewer feature of the program. I then cancelled out the two audio channels, left and right, by inverting one and mixing them together, so that the BTC audio cancelled out and the DHL audio remained behind.