If a takeoff is initiated without
FDs, the system responds as follow:
There are no
FD bars.
There is no
A/THR arming.
There is no guidance available.
The target speed on the
PFD is that selected on the
FCU or is defaulted to 100 kt.
Setting the thrust levers to the
CL detent does not activate
A/THR.
Note: Do not engage the autothrust prior to selecting a target speed on the
FCU.
PROCEDURE
Establish initial climb of 15 °
When reaching the thrust reduction altitude (THR RED ALT):
SELECT a climb speed.
SET the thrust levers to
CL detent.
ACTIVATE the autothrust.
TURN ON the
FDs (basic modes engage).
SELECT appropriate mode.
Failure of both
FDs after the start of takeoff:
The FD bars disappear.
The FCU window displays the target speed, which synchronizes on V2, or the current speed (if it is higher).
The autothrust remains armed.
At thrust reduction altitude, LVRCLB flashes. If the pilot set the thrust levers to the CLB detent, the autothrust becomes active in selected SPD mode (no FDs selected).
If the current speed is greater than the target speed, the thrust decreases.
At acceleration altitude the target speed does not change, since it is selected.
Taken from FCOM/PRO/NOR/SRP/01FMS/TakeOff.
However if you are still using the "old" fcom i believe it's in FCOM 4.5.30
Hope it helps.