DOC AIRBUS | AMM A320FCOCKPIT TO GROUND CREW CALL SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The ground crew call system enables crew member-to-ground mechanic or ground mechanic-to-crew member calls.
It has also an aural warning function when the aircraft is powered by batteries for the systems given below :
** ON A/C NOT FOR ALL The ground crew call system enables crew member-to-ground mechanic or ground mechanic-to-crew member calls.
It has also an aural warning function when the aircraft is powered by batteries for the systems given below :
- APU fire
- ADIRS powered by batteries
- Equipment ventilation faulty.
2. Component Location
** ON A/C NOT FOR ALL 
Ground Crew Call System - Component Location| FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C ALL | |||||
| 15WC | HORN-MECH CALL | 124 | 23-42-21 | ||
3. System Description
The ground crew call system consists of :
** ON A/C NOT FOR ALL The ground crew call system consists of :
- a CALLS/MECH pushbutton switch 1WC located on the overhead panel 21VU in the cockpit. It is associated with the RESET pushbutton switch 12WC located on the panel 108VU of the ground power receptacle.
- a mechanic call horn 15WC located in the nose gear well. The horn sounds to warn the mechanic of a call.
- a COCKPIT CALL indicator light 14WC located on the panel 108VU. This indicator light comes on to warn the mechanic of a call.
- a COCKPIT CALL pushbutton switch 10WC located on the panel 108VU. This pushbutton switch enables the ground mechanic to call the crew members via the circuit WW for the audio function and circuit RN for the visual indication.
4. Power Supply
The ground crew call system is supplied with 28VDC power from the 28VDC HOT BUS 702PP. The system is protected by the circuit breaker 2WC located on the panel 121VU.
** ON A/C NOT FOR ALL The ground crew call system is supplied with 28VDC power from the 28VDC HOT BUS 702PP. The system is protected by the circuit breaker 2WC located on the panel 121VU.
5. Operation
The system operates on the ground only, with the left and right main landing gear shock absorbers compressed. However, in flight or A/C on jacks , if the LGCIU is not energized, the ground crew call is activated following pilot's action.
The system operates on the ground only, with the left and right main landing gear shock absorbers compressed. However, in flight or A/C on jacks , if the LGCIU is not energized, the ground crew call is activated following pilot's action.
A. Ground Mechanic-to-Crew Member Call
When pressing the COCKPIT CALL pushbutton switch 10WC, a ground signal is applied to the FWCs (31-52) triggering the buzzer circuit which feeds the aural warning signal to the loud speakers. This ground signal is applied to the circuit RN for the illumination of the MECH legend on the ACPs.
When pressing the COCKPIT CALL pushbutton switch 10WC, a ground signal is applied to the FWCs (31-52) triggering the buzzer circuit which feeds the aural warning signal to the loud speakers. This ground signal is applied to the circuit RN for the illumination of the MECH legend on the ACPs.
B. Crew Member-to-Ground Mechanic Call
During all the time the pilot presses the CALLS/MECH pushbutton switch 1WC located on the overhead panel, the mechanic call horn sounds. The blue COCKPIT CALL indicator light comes on.
When the pilot releases the CALLS/MECH pushbutton switch, the mechanic call horn stops but the indicator light remains on. This indicator light goes off when the mecanic presses the RESET pushbutton switch 12WC located on the panel 108VU.
In addition, warnings are generated for the following systems :
During all the time the pilot presses the CALLS/MECH pushbutton switch 1WC located on the overhead panel, the mechanic call horn sounds. The blue COCKPIT CALL indicator light comes on.
When the pilot releases the CALLS/MECH pushbutton switch, the mechanic call horn stops but the indicator light remains on. This indicator light goes off when the mecanic presses the RESET pushbutton switch 12WC located on the panel 108VU.
In addition, warnings are generated for the following systems :
- 26-13 APU FIRE on ground
- 21-26 BLOWERS LO FLOW on ground with engines shut down
- 34-14 ADIRS ON BAT on ground with engines shut down.