Originally Posted by
hetfield
If this is the case, and I believe you, again it shows how complex airbus systems are designed.
It's not just Airbus though - note NSEU's experiment on the FPV thread I linked earlier (bolding mine):
Originally Posted by
NSEU
There's an easy way to prove that the FPV does or does not ADC data. Pull the CBs for the ADCs (well, at least this is possible on the Boeings which don't have ADIRUs).
Originally Posted by
NSEU
On the 747-400 (at least) Baro from the ADCs is fed into the IRUs. The IRU's then mix baro and IRU info and send this as IVSI information to the PFD. This is why the IVSI information disappears when either the ADC or IRS CBs are pulled.
...
If the FPV is removed if I pull the ADC CB's, I will be suitably humbled. I'll also check for the presence of the FPV during ATTitude mode.
Originally Posted by
NSEU
OK, I'm suitably impressed. I still don't understand it, but the FPVs did disappear when I pulled all the ADC CBs.
As always, the guys who fix the aircraft are the last to know.
So it seems that at least some Boeing FPVs also disappear when air/baro data goes away.