After reading post #661 ...
Hence, it may be deduced that it was due to a "triple ADR" fault:
=> ADR 1 + 2 / ADR 1 + 3/ ADR 2 + 3 (ECAM)
=> ADR 1 + 2 + 3 (not displayed by ECAM)
Consequently, Low and High Speed protections were lost while "SPD LIM" was flagged on both PFDs without VSw and VMax displayed.
Following so far, these protections are features of Normal Law.
Caveat: the following informed by sources that are between 5 and 10 years old.
When the pilots noted "Alternate Law," speed stability functions should have been in play if they were in Alt 1, but not Alt 2.
The system needs two valid ADR for stall warning and low speed stability.
I look at the FMA, and try to figure out if alert to "Alternate Law" is in one of the five fields above the attitude display, or on the ECAMS page. I cannot. (Don't have anything that tells me.)
Stability function can make inputs but can be overridden by the pilot's inputs.
This makes me wonder: did the crew know if their state was Alt 1 or Alt 2? (There may be more on CVR that will clear this up from next report, but there may not. Likely their work load was up, see below, and as such precluded any discussion as to which Alt mode was in play).
If PF didn't recognize alt 2 versus alt 1, would that have made a difference in how PF made and monitored nose inputs? My guess is no, but it's a guess.
(Question based on not having flown A330 ...)
- ADR 1 & 3 were coherent and valid again before 0211:06.
This leads to the question: were the pilots aware of this?
Perhaps the next reprt, and CVR analysis, release will shed light on that question. Perhaps task load precluded such a realization.
- Another triple ADR fault sequence started "after 0211:40";
- All speeds became invalid again;
From June 2005 revision of the Flight Crew Training Manual (8.110.3)
"... if all three ADRs provide consistent and erroneous data, the PRIMs and FEs will reject the “good” outlier ADR and will continue to operate normally using the two consistent but faulty ADRs."
Interestingly, in another section of the manual (2.60.11)
DIRECT LAW - In most cases of triple failure, e.g. triple ADR failure, direct law is triggered. Autopilot and auto-trim are not available.
One hopes that the various cases are handled in the simulator training sessions.
I also note that around pages 2.30.5 through 2.30.8 some ECAMS crew coordination is disucssed.
The process by which a crew clears ECAMS alerts is organized and formalized, but I see a source of possible scan disruption for the PF in this process, based on standard procedures for clearing ECAMS alerts.