TCAS

Question 1

AP/FD TCAS mode

Answer 1

The AP/FD TCAS mode is a vertical guidance mode of the AP/FD. In the case the TCAS generates a Resolution Advisory (RA) alert, this mode automatically engages to assist the flight crew to follow the RA orders, and to revert toward initial trajectory:

‐ Automatically if the AP is engaged, or

‐ Manually with the guidance of the Flight Director (FD), if the AP is not engaged.

The AP/FD TCAS mode optimizes the vertical speed for a rapid and appropriate response to an RA, and minimizes the deviations from the latest ATC clearance.

When the TCAS is operating in TA ONLY mode, the AP/FD TCAS mode is inhibited.

Question 2

Traffic Advisory (TA)

Answer 2

‐ It generates a visual and aural Traffic Advisory (TA).

‐ In that case, the AP/FD TCAS mode automatically arms:

TCAS appears on the FMA to inform the flight crew that the AP/FD TCAS mode will be available in the case a Resolution Advisory (RA) is subsequently triggered.

Question 3

Resolution Advisory (RA)

Answer 3

It generates a visual and aural Resolution Advisory (RA).

‐ The AP/FD TCAS mode automatically engages: TCAS appears on the FMA.

The flight crew has vertical guidance to fly the RA orders, automatically with the AP/FD, or manually with
the FDs only (if AP was not engaged).

‐ If the A/THR is disconnected, it automatically becomes armed or active, depending on the
thrust lever position.

When A/THR is active, the speed/Mach mode engages, and the speed/Mach control becomes selected.

‐ The vertical speed scale on the PFD indicates the vertical speed range within which the
aircraft should fly.

Question 4

Clear of Conflict

Answer 4

‐ It triggers the “CLEAR OF CONFLICT” aural alert.

‐ In most of the cases, the AP/FD TCAS mode automatically reverts to V/S mode:

The vertical speed target leads the aircraft toward the FCU selected altitude.

If the altitude capture conditions are met at the clear of conflict, the AP/FD TCAS mode can revert to an altitude acquire, or an altitude hold mode