Hi Confiture,
Originally Posted by CONF iture
Do we read a different version of the first interim report ?
Originally Posted by BEA#1 P52
Note: the alternate 2 control law is a load factor law for pitch and a direct law for roll. Only the load factor protection remains available. In certain cases, the high and low speed stabilities may also be lost.
But what's the point after all, still have to work with ACARS messages + BEA note when actually all FDR data have been retrieved ...
First, yes, I guess that we are reading the same report, but I'm trying to include every available informations from it, not only a single quote about the general case above that you underlined from it.
Second, the point is mostly to understand what we already have, before even going further with new data when they will be available (soon).
So, my initial point was to link those ACARS with real cockpit events:
1. Event started at 0210:05 with AP/FD and A/THR faults;
2. Event is due to 2 or 3 PITOT-PROBEs (total pressure) faults affecting some of their respective ADR outputs (barometric altitude, speed, Mach, angle-of-attack, temperature and overspeed warnings);
3. Those PITOT-PROBE faults caused all the following 0210 ACARS to be reported;
4. ALTERNATE LAW 2 was consolidated after monitoring, it was not transient;
5. 2 or 3 ADRs were rejected by FCPCs and FMGCs;
6. There was no "ADR DISAGREE" triggered during the 0210 sequence;
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.
- ADR 1 & 3 were coherent and valid again before 0211:06.
- Another triple ADR fault sequence started "after 0211:40";
- All speeds became invalid again;
=> It may be assumed that aircraft's airspeeds went below 30 kt, they would not be displayed anymore on both PFDs between 0211:40+ and 0212:19+
=> It may be assumed that "ADR DISAGREE" was triggered after this second triple fault was cleared.