1. Yes, I think BEA indicated a possible reason for wanting to climb : the degraded altitude calculation indicated 400ft under target altitude. One must reckon that at this time, its unlikely that any pilot would consider themselves in an emergency and therefore would feel free to descend without proper ATC authorisation
2.
3. You mean that the PF climbed against the PNF's recommendation ?
I read the original transcripts (not translated) and the main problem with them is that the oral tone is lacking, hence it is impossible to know whether some sentences were comments or order. "You are descending now" and "you must descend" are two equally likely translations of "tu descends, là". Impossible to decide between them without hearing it, and even when hearing it it's likely that one could not decide which it was.
We even can read things like "là tu montes, donc tu descends" (literally "here you climb so you descend" which makes no sense in English, again translation problem and tone required)
4. I can bet (and probably could verify if I had time) that all artificial horizons were correct. About the indicated speeds, one should check parameters IAS1, IAS2 and ISISIAS in the recordings, but I believe these were indeed all lost (?) temporarily
5. An aircraft not responding to control inputs would be classified as a catastrophic failure and should not occur more than once per billion flight hours. It was not the case this night.
6. I don't know that for sure, but it does seem a bit stupid to lose the ground indications (GS, attitude, position) of a perfectly working IRS just because the pitot has frozen. So my guess is that Airbus engineers aren't that stupid ?
7. I think nobody knows for sure what was displayed on the PFDs, but there should have been at least an attitude indication on the emergency horizon.
I don't think it would be wise to follow the FDs in an abnormal situation.. And they should switch off on their own if the APs switch off due to lack of information I don't see how FDs could compute orders if the APs cannot.
I'm not appointing blame on anyone here (someone was asking if the French jurisdiction was doing it, just on the preceding page), just pointing out a few basic theoretical facts that imho should be kept in mind in case of such an incident. (because it starts with a simple incident : pitot information loss)
Don't you think the PF could have decided between high speed stall and low speed stall by looking at his GS ? Even with wind, the difference between the two should be in all cases sufficient to decide between high speed and low speed.
We should learn from accidents and try to improve safety. I would suggest these
1. The creation of a color code for each displayed parameter :
- white - normal, confirmed by multiple sources
- other color - abnormal, at least one source disagreeing significantly
- other color - abnormal, no redundance
- red - unreliable or unavailable information
1bis. there could be a new status page indicating which sources are known to be unreliable (e.g computer sending error signals), which sources are feeding information where, and if this information is consistent with other sources
2. The improvement of the standby instruments systems towards a very high reliability even at the cost of a slightly lower precision. For example, maybe the precision of modern DGPS could allow to compute a reasonably accurate attitude indication (with 7 receivers on each extreme point of the aircraft).
My (debatable) idea is that GPS would help confirm values computed by the usual way.
e.g if you measure a -8000fpm GPS descent rate, a -10000fpm indicated VSPD would be confirmed but if 0 fpm was displayed on the PFD, it would trigger an alarm (and color coded indication) (as well as the contrary)