Warning: I'm non-professional; not crew, not engineer - just scientist guest and thanks.
Shawk in post 1110 wrote while discussing fluidic resonance in a tuned circuit:
I believe that witnesses reported that the aircraft made an unusual sound as it approached the airport. While witnesses tend to be unreliable, some weight might be given to this observation as witnesses who work at airports tend to have experience with typical aircraft noise.
If the reports are reliable then it seems more probable that the sound might be due to the high pressure fuel pumps cavitating.
Apologies if this has been mentioned before.
regards, Tanimbar