Originally Posted by SPA83
Has the crew been warned about AoA probes failure ? : NO
Is this an anomaly according to CS 25 ? : YES
Why would they be warned? Strictly speaking, the probes did not fail and it's not an anomaly according to CD 25. They were blocked but they kept working. Not as designed, for sure but there was no (love that Airbusspeak) unequivocal indication of failure. Even the intelligent systems would have problems deciding which data is correct, let alone unintelligent ones, like computers. Two of three agreed so it was simple task. Of course, monday morning quarterbacks now know better, quoting aviation laws while having no basic understanding of the way things work once we slip the surly bonds of earth. 'Tis a pity PBL's plea for the better solution will have to go unanswered.
Subtle failures are not Airbus specific problem; they are aviation specific. Aeroperu 603 had similar problem: blocking of all static ports due to non-standard (transparent) masking tape used to protect static port during washing and not being removed afterwards. Everything worked perfectly during takeoff roll, troubles began when trapped static pressure lost semblance to actual static pressure and the crew was bombarded by the warning for faults that were non-existent. At one point they got stick shaker and overspeed simultaneously and finally, exhausted with battle fell victim to assumption that ATC alt readout is correct one. Do we blame Boeing for that?
Originally Posted by CONFiture
As soon as the AoA data show a discrepancy , it is a the most common sense duty for the manufacturer to clearly advise the crew. At this point the crew will proceed as politely as possible to the end of the flight.
I do agree that having one ADC outvoted for considerable period of time, let's say 15 sec, would be nice to have annunciated via ECAM. However, aeroplane is designed to work perfectly fine with 2 out of 3 operative, it's flyable with all 3 failed and Airbus philosophy is to reduce the nuisance warnings as much as possible so this might go against their grain. IIRC if the aroplane was CAT III DUAL at takeoff, outvoting of ADC would change that to CAT III SINGLE. Yes it's subtle but it's on FMA part of PFD. I tought it was a joke when on introduction to Airbus I was told that FMA is primary flight instrument but was quickly persuaded otherwise. That's also the place where USE MANUAL PITCH TRIM is displayed.
Regarding CHECK GW, it was drummed into me that it's to be taken very seriously because it can be result of either:
1. entering wrong ZFW - most often and easily corrected
2. being secretly grossly overloaded - not a chance for European scheduled operation
3. FACs preparing to turn their little electronic backs on you - very unlikely yet possible. Good luck with this one.
I was mere line F/O, not allowed to go anywhere near flight testing. Lucky me for having instructors that understood Airbus very well and regarded "smart aeroplane" merely sales pitch BS.
Originally Posted by CONFiture
Even better, the crew should be able by a single switch to disable all protection features, making sure they won’t interfere based on faulty information.
They never interfered and that's where the real troubles begun. When the aeroplane started tumbling, all protections went off and only G protection ws recovered before making the water contact. I find neither crew performance nor end result satisfactory.