2 h 12 min 04 to 2 h 12 min 07
PF: J’ai l’impression qu’on a une vitesse de fou non qu’est-ce que vous en pensez ?
I have the impression that we have some crazy speed, don’t we ?.. what do you think ?
There was a comment by HarryMann (
http://www.pprune.org/tech-log/45687...ml#post6610754) that perhaps the PF was hearing a different airflow sound and wrongly associated this with high speed -
absolutely that is possible!
As I noted previously, I have been involved in Level D sound simulations for over 20 years now and would certainly find it likely that the aerohiss heard at an abnormal attitude such as that experienced by AF447 on the way down would likely be similar to the noise normally associated with high Mach.
This would be somewhat similar to the sound when an aircraft achieves some level of sideslip, which is particularly noticeable due to the asymmetric flow of air over the cockpit.
In a stall such as that experienced by AF447, with a significant and unusual AoA, the airflow breaking over the nose and windshield would be turbulent and certainly sound "different". I doubt it would be identical to that of high Mach cruise (which just tends to significantly louder than normal - the change from 0.82M to 0.85M for example is significant in dB terms), but for any pilot I suspect it would be noticeable.
In my comfy office, it is easy to say that the clues were all there - attitude and altitude (or more explicitly rate-of-descent), but I will add this - most simulators would do a very poor job of representing this sound condition - in fact I would so bold as to say they would do a crappy job and would likely generate little, if any sound, since forward airspeed is the driving parameter for the aeronoise sound cues (a combination of Mach and CAS).
As I write this post, I am now attempting to think through what would be needed to drive this abnormal descent sound cue - probably a function of AoA and vertical speed...