DOC AIRBUS | AMM A320FENGINE MASTER CONTROL - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The engine master control switch operates:
** ON A/C NOT FOR ALL The engine master control switch operates:
- The High Pressure (HP) fuel Shutoff Valve (SOV) through the Electronic Engine Control (EEC)
- The Low Pressure (LP) fuel SOV
- The hardware reset of the EEC.
2. Component Location
The engine master control switch is located on the center pedestal in the flight compartment, on the engine start panel (115VU).
** ON A/C NOT FOR ALL The engine master control switch is located on the center pedestal in the flight compartment, on the engine start panel (115VU).
| FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C ALL | |||||
| 2KC | CTL SW-ENG/MASTER 2 | 115VU | 210 | 73-31-00 | |
| 3KC | CTL SW-ENG/MASTER 1 | 115VU | 210 | 73-31-00 | |
3. System Description
The engine master control switch operates the HP and LP fuel SOV. When the master lever switches from the ON to the OFF position, each EEC channel starts a hardware reset.
The Fuel Metering Unit (FMU) contains an Electronic Overspeed System (EOS), which prevents engine against overspeed. EOS is a subsystem controlled by EEC and contains an electro-hydraulic servo valve that closes the HP fuel SOV by EEC channel A or B.
The electro-hydraulic servo valve and the HP fuel SOV are used to shut down the engine when the master lever switches from the ON to the OFF position.
** ON A/C NOT FOR ALL The engine master control switch operates the HP and LP fuel SOV. When the master lever switches from the ON to the OFF position, each EEC channel starts a hardware reset.
The Fuel Metering Unit (FMU) contains an Electronic Overspeed System (EOS), which prevents engine against overspeed. EOS is a subsystem controlled by EEC and contains an electro-hydraulic servo valve that closes the HP fuel SOV by EEC channel A or B.
The electro-hydraulic servo valve and the HP fuel SOV are used to shut down the engine when the master lever switches from the ON to the OFF position.
4. Power Supply
The engine master control switch is power supplied with 28VDC, through circuit breakers located in the Captain cabin, in the overhead panel 49VU.
** ON A/C NOT FOR ALL The engine master control switch is power supplied with 28VDC, through circuit breakers located in the Captain cabin, in the overhead panel 49VU.
HP and LP Fuel Shutoff Valve Power Supplies5. Operation/Control and Indicating
A. HP Fuel SOV
The master lever is commanded by one or two EEC channels. It switches from the ON to the OFF position that causes the engine shutdown in the following modes:
The master lever is commanded by one or two EEC channels. It switches from the ON to the OFF position that causes the engine shutdown in the following modes:
- Nominal shutdown: If the selected master lever signal switches from ON to OFF when the engine is at idle and the aircraft is on the ground, one of two EEC channels energizes the electro-hydraulic servo valve of the HP fuel SOV with EOS circuitry. The channel which do the shutdown, alternates after each engine shutdown. This shutdown switching sequence ensures that each EEC channel's EOS circuitry is tested often.
- Non-nominal shutdown: If the selected master lever signal transitions from ON to OFF position while the engine is not at idle or the aircraft is in the air, the two channels energize their applicable EOS circuitry to ensure that fuel is promptly shut off.
B. LP Fuel SOV
The function of the LP fuel SOV is to control the fuel supply at engine-to-pylon interface. The LP fuel SOV is electronically controlled by:
The function of the LP fuel SOV is to control the fuel supply at engine-to-pylon interface. The LP fuel SOV is electronically controlled by:
- The engine master control switch on the engine start panel (115VU)
- The engine fire pushbutton switch (panel 20VU).