Hi JenCluse,
I'm also feeling your pain as I'm trying to catch-up with this thread after a while.
Originally Posted by JenCluse
(This after skimming over a post which I can't now find, which seemed to suggest that the standby instruments (ICUS, I believe they/it are called) are not fundamental, steam-driven devices, but take their data input from some branch of the computed data stream.)
I can find the printable area, but 40 posts only. I'd like to be able search any discussion point. Anyone?
I understand that you are refering to ISIS and what you think is, in some way, both right and wrong. Stand-by instruments are supplied by analogic pnematic sources: probe pitot 3 and static probe 3. However, both probes are used for direct sensing and/or connected to numerical Air Data Module (ADM). In this case, those ADMs are feeding ADR3 which may replace either ADR1 (Captain probes) and ADR2 (FO probes) while the stand-by gauges (ISIS) are displaying the direct measures from the same probes.
You can also refer to the BEA first report which have a detailed diagram with usefull explanation about Airdata, page 22:
