ATC TCAS Panel

Back to Flight Deck

Description

The aircraft 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.

The XPDR is capable of elementary surveillance (ELS) and enhanced surveillance (EHS). It transmits the following data to the ATC center:

• Supplied by the ADRs:
  • The aircraft 24 bit address
  • The aircraft altitude
  • The flight number
  • The RA report
  • The indicated airspeed
  • The Mach number
  • The barometric vertical speed
• Supplied by the IRs:
  • The magnetic heading
  • The roll angle
  • The ground speed
  • The track angle
  • The track angle rate
  • The inertial vertical speed
• The selected altitude and barometric reference settings supplied by the FCUs.

Usage

Mode Selector

• STBY:
  • Both XPDR are electrically supplied but do not operate.
• ON:
  • Selected XPDR operates.
• AUTO:
  • In flight : Selected XPDR operates.
  • On ground : Selected XPDR only operates in mode S (Selective aircraft interrogation mode).

XPDR Selector

This switch selects XPDR 1 or 2.

ALT RPTG Switch

• ON:
  • The XPDR sends barometric standard altitude data.
• OFF:
  • No altitude data transmission. If the TCAS is installed, the upper ECAM displays "TCAS STBY" in green.

IDNT Switch

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

Code Display

• The window displays the selected code.

Keypad

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

CLR Key

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

ATC FAIL Light

• This light comes on if the selected XPDR fails.

TCAS Mode

TCAS knows the following threat categories:

• Other intruders - white outlined diamond
• Proximate intruders - white diamond
• Traffic Advisory (TA) - amber circle
• Resolution Advisory (RA) - red square

TCAS mode selector:

• TA/RA:
  • If the ALT RPTG switch is ON and the transponder is not on STBY RAs, TAs and proximate intruders are displayed. Default position.
• TA:
  • TCAS only provides Traffic Advisory. 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.
  • "TA ONLY" memo is displayed on the NDs.
• STBY:
  • TCAS is on standby.

TCAS TRAFFIC

• THRT:
  • Proximate and other intruders are displayed only if a TA or RA is present, and they are within 2.700 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 –2.700 ft to +2.700 ft.
• ABV:
  • Same as ALL, except that the other intruders are displayed if within 9.900 ft above and 2.700 ft below the aircraft.
• BLW:
  • Same as ALL, except that the other intruders are displayed if within 9.900 ft below and 2.700 ft above the aircraft.

Back to Flight Deck