DOC AIRBUS | AMM A320FHYDRAULIC POWER - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The aircraft has three main hydraulic systems. They are identified as the Green, Blue and Yellow systems. Together they supply hydraulic power at
3000 psi (206 bar) to the main power users. These include the flight controls, landing gear, cargo doors, brakes and thrust reversers. Services which are not used during flight (cargo doors, brakes, landing gear and nosewheel steering) are isolated from the main supply.
Hydraulic Components - Location ** ON A/C NOT FOR ALL
Hydraulic Components - Location ** ON A/C NOT FOR ALL
Hydraulic Components - Location ** ON A/C NOT FOR ALL
Hydraulic Components - Location ** ON A/C NOT FOR ALL
The three systems are not hydraulically connected. Where possible they are kept apart to keep to a minimum the effect of engine or tire burst, or other damage. There are no hydraulic pipes in the passenger cabin or flight compartment.
High pressure (HP) pipes which are not in fire zones are made of titanium alloy and are not painted. HP pipes in fire zones are made of stainless steel. Low pressure (LP) pipes are made of light alloy and are painted for protection against corrosion. In certain special areas (landing gear bays), the LP pipes are made of stainless steel or titanium alloy. Stainless steel and titanium alloy pipes are electrically bonded with bonding leads and clips. It is not necessary to bond light alloy pipes. Flexible pipes are used where it is necessary because there is vibration or movement between components.
Manifolds are used where possible in both the HP and LP systems. The maximum quantity of components are installed on the manifolds to prevent damage to or movement of the pipes when components are replaced. The manifolds have bobbin type connections for some components.
The seal drains of some components (emergency generator, power control units, power transfer unit and electric pumps) and the pressure relief valves of the reservoirs are connected to the seal drain system. This system collects the fluid leakage from these components and keeps it in containers which can be emptied on the ground. This prevents the collection of hydraulic fluid in the aircraft structure where it may cause a risk of fire.
An air bleed from the pneumatic system of the aircraft pressurizes the reservoirs to 50 psi (3.5 bar) . This makes sure that there is a sufficient supply of fluid to the pumps in all conditions.
There are electrically-operated motorized valves in the suction lines to the two engine pumps. They close automatically when the engine fire handles are operated and stop the supply of hydraulic fluid to the pump.
** ON A/C NOT FOR ALL The aircraft has three main hydraulic systems. They are identified as the Green, Blue and Yellow systems. Together they supply hydraulic power at
3000 psi (206 bar) to the main power users. These include the flight controls, landing gear, cargo doors, brakes and thrust reversers. Services which are not used during flight (cargo doors, brakes, landing gear and nosewheel steering) are isolated from the main supply.
Hydraulic Components - Location ** ON A/C NOT FOR ALL Hydraulic Components - Location ** ON A/C NOT FOR ALL Hydraulic Components - Location ** ON A/C NOT FOR ALL Hydraulic Components - Location ** ON A/C NOT FOR ALL The three systems are not hydraulically connected. Where possible they are kept apart to keep to a minimum the effect of engine or tire burst, or other damage. There are no hydraulic pipes in the passenger cabin or flight compartment.
High pressure (HP) pipes which are not in fire zones are made of titanium alloy and are not painted. HP pipes in fire zones are made of stainless steel. Low pressure (LP) pipes are made of light alloy and are painted for protection against corrosion. In certain special areas (landing gear bays), the LP pipes are made of stainless steel or titanium alloy. Stainless steel and titanium alloy pipes are electrically bonded with bonding leads and clips. It is not necessary to bond light alloy pipes. Flexible pipes are used where it is necessary because there is vibration or movement between components.
Manifolds are used where possible in both the HP and LP systems. The maximum quantity of components are installed on the manifolds to prevent damage to or movement of the pipes when components are replaced. The manifolds have bobbin type connections for some components.
The seal drains of some components (emergency generator, power control units, power transfer unit and electric pumps) and the pressure relief valves of the reservoirs are connected to the seal drain system. This system collects the fluid leakage from these components and keeps it in containers which can be emptied on the ground. This prevents the collection of hydraulic fluid in the aircraft structure where it may cause a risk of fire.
An air bleed from the pneumatic system of the aircraft pressurizes the reservoirs to 50 psi (3.5 bar) . This makes sure that there is a sufficient supply of fluid to the pumps in all conditions.
There are electrically-operated motorized valves in the suction lines to the two engine pumps. They close automatically when the engine fire handles are operated and stop the supply of hydraulic fluid to the pump.
2. System Description
A. Main System
Hydraulic Power - Schematic ** ON A/C NOT FOR ALL
Hydraulic Power - Schematic ** ON A/C NOT FOR ALL
Hydraulic Power - Schematic ** ON A/C NOT FOR ALL
Hydraulic Power - Schematic ** ON A/C NOT FOR ALL
Hydraulic Power - Schematic ** ON A/C NOT FOR ALL
Hydraulic Power - Schematic ** ON A/C NOT FOR ALL
Line Routing of Forward Part ** ON A/C NOT FOR ALL
Line Routing of Forward Part ** ON A/C NOT FOR ALL
The three systems are each pressurized by one main pump. The Green system pump is connected to the left engine and the Yellow system pump is connected to the right engine. The Green and Yellow pumps supply hydraulic power when their engine operates. The electric pump of the Blue system starts automatically when any one of the engines operates. The three system main pumps are usually set to operate permanently. If necessary (because of a system fault, or for servicing), the pumps can be set to off from the flight compartment.
Most of the components of the systems are in the three hydraulic compartments. The Green system components are in the main landing gear compartment. The Yellow system components are in the hydraulic compartment in the right belly fairing. The Blue system components are in the hydraulic compartment in the left belly fairing. The two hydraulic compartments (Blue and Yellow) are forward of the main landing-gear compartment.
There are three ground service panels, one for each main system. The Blue and Green ground service panels are in the left belly fairing. The Yellow ground service panel is in the right belly fairing. All of the ground service panels are aft of the main landing-gear compartment.
All of the ground service panels have self-sealing connectors for hydraulic power supply on the ground. The ground service panel of the Green system has a hand pump, filter and selector valve so that any of the reservoirs can be filled from it. The ground service panel of the Yellow system has a hand pump and selector valve. They give an alternate method to operate the cargo doors. The ground service panel of the Blue system has the ram air turbine control panel.
Hydraulic Power - Schematic ** ON A/C NOT FOR ALL Hydraulic Power - Schematic ** ON A/C NOT FOR ALL Hydraulic Power - Schematic ** ON A/C NOT FOR ALL Hydraulic Power - Schematic ** ON A/C NOT FOR ALL Hydraulic Power - Schematic ** ON A/C NOT FOR ALL Hydraulic Power - Schematic ** ON A/C NOT FOR ALL Line Routing of Forward Part ** ON A/C NOT FOR ALL Line Routing of Forward Part ** ON A/C NOT FOR ALL Most of the components of the systems are in the three hydraulic compartments. The Green system components are in the main landing gear compartment. The Yellow system components are in the hydraulic compartment in the right belly fairing. The Blue system components are in the hydraulic compartment in the left belly fairing. The two hydraulic compartments (Blue and Yellow) are forward of the main landing-gear compartment.
There are three ground service panels, one for each main system. The Blue and Green ground service panels are in the left belly fairing. The Yellow ground service panel is in the right belly fairing. All of the ground service panels are aft of the main landing-gear compartment.
All of the ground service panels have self-sealing connectors for hydraulic power supply on the ground. The ground service panel of the Green system has a hand pump, filter and selector valve so that any of the reservoirs can be filled from it. The ground service panel of the Yellow system has a hand pump and selector valve. They give an alternate method to operate the cargo doors. The ground service panel of the Blue system has the ram air turbine control panel.
B. Auxiliary Systems
The auxiliary hydraulic power generation systems are:
The PTU of the Green/Yellow system is in the main landing gear compartment. It can operate in two directions, Green to Yellow, or Yellow to Green. There is no hydraulic connection between the two hydraulic systems. The PTU operates automatically when there is a difference in pressure between the two systems of 500 psi (35 bar). The PTU is permanently available, but can be set to off from the flight compartment if necessary. There is a quick-release self-sealing coupling which isolates the PTU to stop one system pressurizing the other during servicing.
The Yellow electric pump is in the Yellow hydraulic compartment. It supplies the Yellow main system with hydraulic power when necessary (failure of the engine or engine pump). It is set to on from the flight compartment. It also starts when the aircraft is on the ground and a selection is made to operate the cargo doors.
The hand pump of the Yellow system is on the Yellow ground service panel. It is used to operate the cargo doors if no electric power is available.
The auxiliary hydraulic power generation systems are:
- the Ram Air Turbine (RAT) of the Blue system,
- the Power Transfer Unit (PTU) of the Green/Yellow system,
- the electric and hand pumps of the Yellow system.
NOTE: The Blue Electric pump can be used as a auxiliary power unit for maintenance purposes when the aircraft is on the ground.
The RAT of the Blue system is in a compartment in the left belly fairing, forward of the main landing-gear compartment. It extends into the airflow automatically when there is a total failure of AC busbars 1XP and 2XP. The crew can operate it from the flight compartment if necessary. The RAT supplies hydraulic power to the Blue system. If there is an electrical failure, the RAT also supplies the controlled speed motor generator (CSM/G) which gives electrical power to the aircraft. The PTU of the Green/Yellow system is in the main landing gear compartment. It can operate in two directions, Green to Yellow, or Yellow to Green. There is no hydraulic connection between the two hydraulic systems. The PTU operates automatically when there is a difference in pressure between the two systems of 500 psi (35 bar). The PTU is permanently available, but can be set to off from the flight compartment if necessary. There is a quick-release self-sealing coupling which isolates the PTU to stop one system pressurizing the other during servicing.
The Yellow electric pump is in the Yellow hydraulic compartment. It supplies the Yellow main system with hydraulic power when necessary (failure of the engine or engine pump). It is set to on from the flight compartment. It also starts when the aircraft is on the ground and a selection is made to operate the cargo doors.
The hand pump of the Yellow system is on the Yellow ground service panel. It is used to operate the cargo doors if no electric power is available.
3. Power Supply
The hydraulic system gets electrical power from the AC and DC systems of the aircraft.
These circuits have a 115 V AC supply:
These circuits have a 28 V DC supply:
This circuit has a 26 V AC supply:
** ON A/C NOT FOR ALL The hydraulic system gets electrical power from the AC and DC systems of the aircraft.
These circuits have a 115 V AC supply:
- the electric pump of the Yellow system,
- the electric pump of the Blue system.
These circuits have a 28 V DC supply:
- RAT,
- the monitoring and control circuit of the Green system pump,
- the monitoring and control circuit of the Yellow system (engine-driven) pump,
- the warning and control circuit of the Blue system,
- Eng 1 and Eng 2 fire valves,
- the low level indicator circuit of the reservoirs,
- the system pressure transmitters,
- the leak test solenoid valves,
- the PTU solenoid valves,
- the Yellow auxiliary system.
This circuit has a 26 V AC supply:
- Reservoir Quantity Indication System
A. Control
Control of the main systems is usually automatic but the crew can control the systems from the flight compartment when necessary. Most of the controls are on the two overhead panels 40VU and 50VU.
Panel 40VU has the pushbutton switches for:
It also has the RAT hydraulic override switch to deploy the RAT. Panel 50VU has the pushbutton switches which control the three leakage measurement selectors. These are used for servicing only. Also on panel 50VU is the override switch of the Blue electric pump. This switch makes it possible to operate the electric pump of the Blue system when the aircraft is on the ground and the two engines are stopped.
The FIRE pushbutton switches on the overhead panel (section 20VU) control the motorized valves in the suction lines to the engine pumps.
The electrical override switch to deploy the RAT is on panel 21VU.
Control of the main systems is usually automatic but the crew can control the systems from the flight compartment when necessary. Most of the controls are on the two overhead panels 40VU and 50VU.
Panel 40VU has the pushbutton switches for:
- engine No. 1 Hydr. pump (Green),
- engine No. 2 Hydr. pump (Yellow),
- electric pump (Blue),
- PTU,
- electric pump (Yellow).
It also has the RAT hydraulic override switch to deploy the RAT. Panel 50VU has the pushbutton switches which control the three leakage measurement selectors. These are used for servicing only. Also on panel 50VU is the override switch of the Blue electric pump. This switch makes it possible to operate the electric pump of the Blue system when the aircraft is on the ground and the two engines are stopped.
The FIRE pushbutton switches on the overhead panel (section 20VU) control the motorized valves in the suction lines to the engine pumps.
The electrical override switch to deploy the RAT is on panel 21VU.
B. Indication
There are two primary types of indication. They are:
There are two primary types of indication. They are:
- mechanical, which are gages in the hydraulic compartments and wings. These include pressure gages on the system accumulators, air pressure gages on the reservoirs and contents gages on the reservoirs. The content of the three reservoirs is also shown on the reservoir quantity indicator (1834GQ) on the ground service panel of the Green system.
- indications related to the electronic centralized aircraft monitoring (ECAM) system. These are shown on the HYD page of the system display, the engine/warning display and on the overhead panel.