Gentlemen above have differing opinions about how the flight guidance understands what is the final approach speed: OVHD or MCDU? It is part of the OP's query too.
I am trying to find a reference, and not being very successful with it.
The OVHD panel pb LDG FLAP 3 is part of the GPWS panel
Originally Posted by DSC-34-SURV-40-40 A SURVEILLANCE
GPWS - CONTROLS AND INDICATORS: OVERHEAD PANEL
(4) LDG FLAP 3 pushbutton
ON : Flap mode is inhibited when FLAPS CONF 3 is selected (to avoid nuisance warning in case of landing in CONF 3). In this case, LDG MEMO displays "FLAPS ... 3" instead of “CONF ... FULL”.
Neither has the MCDU page description any clues
Originally Posted by DSC-22_20-50-10-25 AY: PERF APPR Page
[4R] LDG CONF CONF 3
The flight crew can select configuration 3 by pressing the 4R key. This moves the * down to the [5R] field, which is displaying “FULL".
[5R] FULL
The flight crew can use this key to select configuration FULL when
necessary configuration FULL is the default landing configuration.
And no luck finding anything in
. DSC AUTOFLIGHT - A/THR
. DSC AUTOFLIGHT - Speeds Definition
. DSC F/CTL
However PRO-NOR-SOP-16-A DESCENT PREPARATION: PERF APPR says
"Check or modify the landing configuration. Always select the landing configuration on the PERF APP page: ..."
I went to FCTM: nothing found. QRH: same result.
