Flight Guidance

Question 1

There is a direct relationship between aircraft pitch control, and engine thrust control.
This relationship is designed to manage the aircraft’s energy:

If the AP/FD pitch mode controls a vertical trajectory (e.g. ALT, V/S, FPA, G/S):
→ A/THR controls…….

If the AP/FD pitch mode controls a speed (e.g. OP CLB, OP DES):
→ A/THR controls…..

If no AP/FD pitch mode is engaged (i.e. AP is off and FD is off):
→ A/THR controls speed.

Therefore, any change in the AP/FD pitch mode is associated with a change in the A/THR mode.

Note:
For this reason, the FMA displays the A/THR mode and the AP/FD vertical mode columns next to each other.

Answer 1

speed

thrust (THR CLB, THR IDLE)

Question 2

Vertical managed modes can only be used, if the lateral managed NAV mode is used.
If the flight crew decides to divert from the lateral F-PLN, the autopilot will no longer guide the aircraft along the vertical F-PLN.
Therefore if HDG or Track are selected in a climb, CLB will revert to….
In a Descent if HDG or TRK is engaged, the vertical mode reverts to

Answer 2

OP CLB

V/S or FPA.

Question 3

The “triple click” is an aural alert. It is an attention-getter, designed to draw the flight crew’s attention to the…….

The PFD FMA highlights a mode change or reversion with a white or amber box around the new mode, and the pulsing of its associated FD symbol.

The reversions, described in the previous paragraph, are also emphasized via the triple click aural alert.

Note:
The triple click also appears in the following, less usual, cases:

SRS → CLB (OP CLB) reversion: If the flight crew selects a speed on the AFS CP
The V/S selection is «refused» during ALT: The flight crew pulls the V/S knob, while in ALT
The V/S target is not followed, because the selected target is too high, and leads to VMIN/VMAX.

Answer 3

FMA