A320 ATC/TCAS PANEL

The Airbus A320 has two ATC transponders (XPDR) which are controlled by a control panel (ATC/TCAS)
on the center pedestal. Only the selected XPDR operates.

The XPDR automatically responds to requests:

• From the ATC, to ensure effective air traffic surveillance.
• From other aircraft that have a TCAS, to ensure that traffic alerts are triggered.

ALT RPTG sel

ON : The XPDR sends barometric standard altitude data.
OFF : No altitude data transmission. With TCAS, the upper ECAM displays TCAS STBY during flight phases other than 6, or TCAS STBY during flight phase 6.

ATC FAIL light

This light comes on if the selected XPDR fails.

CLR KEY

The flight crew uses this key to clear the code window.
Note: As long as the four figures of the new code are not entirely written, the previous code remains.

CODE window

The code window displays the selected code.

IDENT pb

The flight crew presses this button to send the aircraft identification signal.

KEYPAD

The flight crew uses the keypad to set the code assigned by ATC.

MODE sel

STBY : Both XPDRs are electrically supplied but do not operate.

ON :

• In flight: The selected XPDR operates. 
• On ground: The selected XPDR only operates in mode S (Selective aircraft interrogation mode).

AUTO :

• In flight: The selected XPDR operates. 
• On ground: The selected XPDR only operates in mode S (Selective aircraft interrogation mode).

XPDR sel

This switch selects XPDR 1 or 2.

TCAS Mode sel

• TA/RA : Normal position.
  The RAs, TAs and proximate intruders are displayed if the ALT RPTG switch is ON and the transponder is not on STBY. 
• TA : The TCAS does not generate any vertical orders. This mode should be used, in case of degraded aircraft performance (engine failure, landing gear extended, or approach on parallel runways).
  All RAs are converted into TAs. TAs, proximate and intruders are displayed if the ALT RPTG switch is ON and the transponder is not on STBY The “TA ONLY” white memo is displayed on the NDs. 
• STBY : The TCAS is on standby.

TCAS TRAFFIC sel

• THRT : Proximate and other intruders are displayed only if a TA or RA is present, and they are within 2700 ft above and 2 700 ft below the aircraft.
• ALL : Proximate and other intruders are displayed even if no TA or RA is present (full time function). The altitude range is – 2700 ft to + 2700 ft. 
• ABV : The same as ALL, except that the other intruders are displayed if within 9 900 ft above the aircraft and 2 700 ft below.
• BLW : The same as ALL, except that the other intruders are displayed if within 9 900 ft below the aircraft and 2700 ft above.