Originally Posted by
mm43
I'm not arguing that, but trying to make the point that once in ALT2b the FCS will seek to maintain 1g, and if the THS Wheel starts to move backwards (NU) the likely reason is the IAS is dropping, and/or you are holding the SS in NU position. Take your pick.
I'll be careful in an attempt not to put my foot in my mouth, but the "maintaining 1G" (or thereabouts) applies in both Normal and Alternate laws. If I recall correctly, the A320's EFCS would interpret that more-or-less literally, and manual S&L flight would actually induce an (extremely) gradual altitude gain (on the level of a few feet per hour) under manual control. This was compensated for and corrected in the A330/340.
I digress - anyway, as I understand it, the deal with ALTN2B is that the "low speed stability" function (i.e. "soft" protection) doesn't work, which means that theoretically:
Originally Posted by
Owain Glyndwr
Below 1.3Vs the aircraft is speed unstable and this is where the BEA comment to the effect that the aircraft might drift to stall even with zero stick input becomes valid.
This has nothing to do with autotrim or THS. Every point made in this regard thus far appears to be educated guesswork. The only way to know would be to take an A330-200 up and try the theory out. A level-D sim might get close to it, presuming that the emulation is correct.
Originally Posted by
tartare
...will the EFIS in an airliner simply peg out at around 40 degrees nose up?
No. Not in the least. Which part of the article are you referring to?
Originally Posted by
Bpalmer
Due to some questionable design choices, AOA was deemed unusable with indicated airspeed below 60KIAS
Well, hold on a minute there. If the manufacturer of the AoA vanes specifies that their output is unreliable below 60kts, how else are you supposed to implement the system? Remember that the A330 and 340 were originally certified with the Goodrich pitot tubes (never known to suffer a dual/triple failure), and the Thales AA fit was an option later in the type's lifecycle.