29. Hydraulic

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A320 – HYDRAULIC

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A320 – HYDRAULIC

• OVERVIEW

• SYSTEM

DESCRIPTION

• SYSTEM

DESCRIPTION

• NORMAL OPERATION

• ABNORMAL

OPERATION

• ABNORMAL

OPERATION

• QUIZ

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A320 – HYDRAULIC

SYSTEM OVERVIEW

A320 – HYDRAULIC

SYSTEM OVERVIEW

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The A320 features 3 hydraulic systems. To make things easy, let’s call them GREEN, BLUE and

YELLOW. They operate continuously at 3000 psi. Transfer of fluid between systems is NOT possible. Every system has its own reservoir.

A IR B U S A 3 2 0 – H Y D R A U L IC G RSVR B RSVR Y RSVR

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Each system has its own pump or pumps, which provide hydraulic pressure to feed the different users such us landing gear, reversers, flight controls, etc. The fluid then comes back to the reservoir.

A IR B U S A 3 2 0 – H Y D R A U L IC G RSVR B RSVR Y RSVR PUM P PUMP S PUMPS

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The three systems feature accumulators, priority valves, shutoff valves, filters and leak

measurement valves. This will be reviewed later in detail. It is also possible to transfer PRESSURE (not fluid) from the GREEN system to the YELLOW and vice versa.

A IR B U S A 3 2 0 – H Y D R A U L IC G RSVR B RSVR Y RSVR PUM P PUMP S PUMPS

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A320 – HYDRAULIC

SYSTEM DESCRIPTION

A320 – HYDRAULIC

SYSTEM DESCRIPTION

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The green pump is powered by engine 1. A IR B U S A 3 2 0 – H Y D R A U L IC

1

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The blue system is pressurized by an electric pump. There is also a Ram Air Turbine (RAT) available to be used in abnormal operations.

A IR B U S A 3 2 0 – H Y D R A U L IC

1

ELE C RA T

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The yellow main pump is driven by engine 2. If the engines are stopped, hydraulic power is available through an electric pump. If there is no electrical power at all, the cargo doors can be operated with a hand pump.

A IR B U S A 3 2 0 – H Y D R A U L IC ELE C RA T ELE C

1

2

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The layout is easy to remember using the “1, 2, 3” rule: The GREEN system has 1 PUMP, the

BLUE one has 2 PUMPS, and the YELLOW one has 3 PUMPS.

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There is also a bidirectional Power Transfer Unit (PTU) which allows the yellow system to pressurize the green system and vice versa. It turns on if the differential pressure between the two systems exceeds 500 PSI. Note that no fluid at all is being transferred.

PT

U

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A320 – HYDRAULIC

ADDITIONAL COMPONENTS

A320 – HYDRAULIC

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SYSTEM ACCUMULATORS

There are one accumulator per system to cope with transient demands and provide with some reserve pressure when no pump is working at all.

A IR B U S A 3 2 0 – H Y D R A U L IC ACC U ACC U ACC U

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PRIORITY VALVES

If the system pressure gets low, priority valves will cut off power to heavy load users such as landing gear, slats, flaps and the emergency generator.

A IR B U S A 3 2 0 – H Y D R A U L IC GREEN HEAVY USERS • LANDING GEAR • _{SLATS &} FLAPS USERS BLUE HEAVY USERS • EMER GEN • SLATS USERS YELLOW HEAVY USERS • FLAPS USERS PR VAL VE PR VAL VE PR VAL VE

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FIRE SHUTOFF VALVES

The green and yellow systems feature a shutoff valve each which can be closed by the crew during abnormal operations. This is done by pressing the ENG 1(2) FIRE pushbutton.

1

ENG PUMP SHUTO FF VALVE SHUTO FF VALVE

2

ENG PUMP

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LEAK MEASUREMENT VALVES AND FILTERS

In order to measure the leakage in each system, three leak measurement valves have been set upstream of the accumulators and the primary flight controls. They can be closed through their own pushbuttons in the cockpit maintenance panel. Several filters are also installed to clean the fluid all thorough the system.

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RESERVOIR PRESSURIZATION

The reservoirs are pressurized with HP bleed air from engine 1. If this pressure is too low, the system takes bleed air from the crossbleed duct.

1

XBLEE D DUCT

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DISTRIBUTION

Get familiar with the users of the three different systems. Be aware that this layout may change depending on the serial number. For example, the Nose Wheel Steering may be powered by the yellow system as well.

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A320 – HYDRAULIC

INDICATIONS

A320 – HYDRAULIC

INDICATIONS

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ECAM HYD PAGE

We are in cruise making good progress.

Please call the ECAM HYD PAGE now.

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ECAM HYD PAGE

Well done. This is the HYD page during normal operations in-flight. The three systems are working properly. Let’s take a look at the meaning of every symbol in there. A IR B U S A 3 2 0 – H Y D R A U L IC

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ECAM HYD PAGE

As you can see on the screen, the nominal pressure of every system is indicated on the top, together with the system label. All pumps provide 3000 psi, except the RAT which works at 2500 psi (emergency only).

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ECAM HYD PAGE

If system pressure is above 1450 psi, the system line, the pressure indication and the triangle on top are green. The system label remains white. Otherwise all of them become amber.

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ECAM HYD PAGE

Moreover, the three squares (one per system) represent each of the main pumps, with the label “1” and “2” for the engine-driven pumps and “ELEC” for the blue electrical pump.

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ECAM HYD PAGE

[Aquí se continua con los distintos símbolos de la página con fotos sacadas del VPT]

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TRIPLE INDICATOR

[Aquí van una foto con el triple indicador y el significado de los indicadores]

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A320 – HYDRAULIC

CONTROLS

A320 – HYDRAULIC

CONTROLS

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MAIN HYD PANEL

The main hydraulic panel is located in the upper area of the systems overhead panel.

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MAIN HYD PANEL

The panel features pushbutton switches for the main pumps, the yellow electrical pump and the PTU. There is also a pushbutton for the manual extension of the RAT, guarded in red.

A IR B U S A 3 2 0 – H Y D R A U L IC GREE N PUM P BLUE PUMP (GUARDE D) YELLO W PUMP YELLO W ELEC PUMP

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A320 – HYDRAULIC

NORMAL OPERATION

A320 – HYDRAULIC

NORMAL OPERATION

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COCKPIT PREPARATION

As per the Airbus general rule, all white lights must be extinguished during the scan. It is mandatory to get clearance from the ground crew before applying hydraulic power, since some parts of the airplane may move and cause serious harm.

A IR B U S A 3 2 0 – H Y D R A U L IC DO NOT APPLY HYDRAULIC POWER WITHOUT GROUND PERSONNEL CLEARANCE!

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The accumulator pressure indication must be in the green band. If it is not, turn on the yellow electric pump to recharge the accumulator. Remember: ask for ground clearance first!

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Let´s put you find the accumulator pressure low. Please get it back to the green band using the yellow elec pump.

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COCKPIT PREPARATION Well done! A IR B U S A 3 2 0 – H Y D R A U L IC

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ENGINE START

The GREEN and YELLOW pumps will start working when their corresponding engine spools up. The

BLUE pump will automatically be turned on after the first engine start.

The PTU will perform a self-test during engine start-up. A PTU FAULT is triggered if the second engine is started within 40 seconds after the end of the cargo doors operation.

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IN-FLIGHT

During the cruise scan, the ECAM HYD page should be reviewed. If you see a slight decrease in quantity, it is normal. Particularly the green system is lower than on ground because of the landing gear retraction.

Fluid contraction during cold soak can also be expected.

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A320 – HYDRAULIC

ABNORMAL OPERATION

A320 – HYDRAULIC

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HYDRAULIC ABNORMALS

The simple hydraulic abnormal procedures will follow this basic guideline:

1. The system will try to recover automatically the affected part by means of the PTU (if applicable).

[Aquí va un pantallazo del ECAM]

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2. The ECAM will tell the pilot to turn off the affected PUMP and, in case of GREEN or YELLOW LOW LEVEL or OVERHEAT, switch off the PTU to prevent the overheat condition to spread.

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3. If a system is lost, then the landing distance will be affected since the spoilers, reversers and braking are hydraulically powered.

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4. If an overheat condition disappears during the approach (FAULT light extinguishes), the system may be recovered.

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A IR B U S A 3 2 0 – H Y D R A U L IC EXAMPLES

[Aquí van un par de ejemplos con lo que saquemos del VPT]

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DOUBLE HYDRAULIC FAILURES A IR B U S A 3 2 0 – H Y D R A U L IC

[Aquí va material con lo que saquemos del VPT]