A320 tech q.
A320 tech q.
Hi everyone,
Was thinking about this the other day. The PFD as you all know displays the characteristic speeds as calculated by the FACs (aerodynamic data). While the FMGS has got the speeds based on estimated weight (ZFW input+FOB).
What is the actual commanded target speed for the A/THR when the approach phase is active in managed speed? Will it aim for the FMGS speed? Allowing the aircraft to fly below S and F as displayed on the PFD? (when the FAC calc. speeds are higher than the FMGS speeds). Or will it hold the speed at the PFD displayed S, F and GD.
What about vice-versa. If the FAC calculated speeds on the PFD are in fact lower than the ones in the FMGS. Will the A/THR hold the FMGS speed or will it go down to the PFD (FAC) speeds?
My guess is that it will fly the one speed whichever is higher. But couldn't find any reference.
I have read the FCOM bulletin regarding the calculation of characteristic speeds but it doesn't talk about A/THR speed targets in case of discrepancies between FAC and FMGS calculated speeds.
Thanks
S.