4 ms·

Why did they need the spectrogram?

• petercooper 5mo ago
  I'm only an ardent viewer of crash investigation stuff, not a pro, but it seems to be a good way to show specifics of warning noises, engine sounds, unusual cabin noises (if relevant) and sometimes even structural failures happening over time in a more direct way from the cockpit voice recorder without sharing the actual "audio".
• sokoloff 5mo ago
  Where else would they get sounds from inside the cockpit that weren’t transmitted on the radio?
• SR2Z 5mo ago
  A distressed airplane makes a lot of noises which are very difficult for the human ear to pick out and identify. For example, multiple closely-spaced bangs or rumbling noises will appear distinctly on a spectrogram but will be very hard to hear.
• bragr 5mo ago
  Basically they were just trying to track down weird noises on the recording. They also went and recorded audio on a similar UPS MD-11 to try to identify the source. According to the NTSB: "This high pitch ringing sound, primarily noted at approximately 6.35 kHz, occurred at 17:13:05.5 EST, shortly after the aircraft rotated for takeoff, and continued with varying amplitude throughout the remainder of the recording. Additionally, a tone at about 2.1 kHz was present along with the ringing that could not be identified."