Pneumatic System Flashcards by Robin Biddulph

The pneumatic system supplies high pressure bleed air for……

Air conditioning
Engine starting
Wing Anti-icing
Water pressurisation
Hydraulic reservoir pressurisation

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High Pressure Air has 3 sources:

Engine Bleed
APU load compressor
HP Ground connection

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What components monitor and control the operation of the pneumatic system?

2 Bleed Monitoring Computers (BMC1 & BMC2)
The overhead control panel
The ECAM

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How many BMC’s operate at the same time?

Each BMC controls and monitors its’ onside engine bleed air system

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Are the BMC’s connected to each other?

Yes

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What information does each BMC receive?

Bleed Pressure
Bleed temperature
Valve position

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Where is air normally bled from for Bleed air supply?

Intermediate stage (IP) of the engines HP compressor

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When would the bleed air come from the HP stage?

At low engine speed, when the pressure and temperature of the IP air are too low.

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When bleed air is coming from the HP stage, what pressure is it maintained at?

36 +-4 psi

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When does the HP valve close automatically:

Pneumatically?

Low upstream pressure

- Excessive upstream pressure

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When does the HP valve close automatically:

Electrically?

-Bleed valve closed by BLEED pb

-Overpressure upstream of the HP valve with:
Wing Anti-ice OFF
2 Packs ON
Aircraft Altitude above 15000ft

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What is the delivery pressure of the Bleed Vlave?

45 +-5 psi

fluctuating between 38-56 psi (max peak to peak 16 psi) at high engine power up to FL100

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The bleed valve is closed pneumatically?

If upstream pressure <8 psi

- If there’s return flow

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The bleed valve is closed electrically?

BLEED pb OFF
ENG FIRE pb pushed
BMC: 
     Overtemp
     Overpressure
     Leak
     Open starter valve
     APU bleed ON

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If pressure regulation of the Bleed valve fails at what pressure does the overpressure valve close?

> 75 psi

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If APU bleed is ON and the crossbleed valve is SHUT, will Engine 2 bleed valve remain open?

Yes

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What regulates the temperature of the Bleed air?

The pre-cooler

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Where does the pre-cooler source its cooling air from for the air-to-air heat exchanger?

Engine fan via the fan air valve.

A spring keeps the fan air valve closed in the absence of pressure

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What temperature does the pre-cooler regulate the bleed air to?

200 degC

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When will the APU supply bleed air to the pneumatic system?

APU BLEED pb ON, and

APU speed >95%

When APU bleed is ON, what is the position of the Engine Bleed and Crossbleed valves?

Crossbleed valve is OPEN

Engine Bleed valves are CLOSED, automatically

When will the APU BLEED valve close automatically?

In the case of:
APU leak
Left wing leak
Pylon 1 leak

(except during engine start)

In automatic mode, when will the cross bleed valve open?

When the system uses APU bleed air

In automatic mode, when will the cross bleed valve close?

If the system detects an air leak (except during engine start)

Leak detection loops detect any overheating near the hot air ducts in the ......?

Fuselage (APU signal) Pylons Wings

Are single or double loops used for leak detection?

Pylon and APU -single | Wing -double

Are two wing loops required for leak detection?

No, a leak can also be detected if one loop detects a leak and the other is inoperative.

A Wing or Pylon leak signal causes.....?

- BLEED valve on related side to close - Assoc. FAULT light - X-Bleed valve to close (except during engine start) -If APU Bleed valve is open and leak concerns Pylon 1, APU BLEED to close (except during engine start)

An APU leak signal causes....?

- APU BLEED valve to close (except during engine start) - FAULT light in APU BLEED pb - X-Bleed valve to close (except during engine start)

If one BMC fails, which ECAMs does the adjacent BMC take over the monitoring of?

- Over pressure - Over temperature - Wing Leak

If One BMC fails is the associated FAULT light in the BLEED pb available?

No, the FAULT light will NOT illuminate if theres a problem

Which ECAM is lost if a BMC fails?

ENG BLEED LEAK (pylon) for the associated engine

Which additional ECAM is lost if BMC 1 fails?

APU BLEED LEAK

Will the cross bleed valve close automatically if a BMC has failed?

Engine BLEED pb ON: | Bleed valve opens if....?

``` Upstream pressure >8 psi APU BLEED pb OFF or APU bleed valve closed No onside wing or pylon leak No overpressure / overtemperature ENG FIRE has not been pushed Engine start valve closed ```

ENG BLEED FAULT light comes on amber and ECAM caution appears if:

- Overpressure downstream of bleed valve - Bleed air overheat - Wing or pylon leak on related side - Bleed valve not closed during engine start - Bleed valve not closed with APU bleed ON

Which valves close when the ENG BLEED pb is switched OFF?

Bleed Valve and HP valve close

APU BLEED pb ON. | Valve opens if...?

- APU N >95% - No leak in APU - No leak in left side bleed (if there is a leak in right side, x-bleed valve closes)

When will the APU BLEED amber FAULT light illuminate?

When the system detects an APU leak

When does the normally green precooler inlet pressure become amber?

<4 psi, or If overpressure detected by BMC (>57-60 psi)

When does the normally green precooler outlet temperature become amber?

If BMC detects an overheat or low temperature:

What are the precooler overheat temperature limitations?

290°C for >5sec 270°C for >15sec 257°C for >55sec

When is precooler low temperature detected and at what temperature?

In flight only, temp <150°C, with Wing Anti-ice ON, and PRV in open position NB. When engines are at idle and depending on ambient temperature, the precooler outlet temperature may be below 150°C (displayed amber)

What does the GND HP connection indication on the system page indicate?

It is possible to connect to the HP ground air supply. It appears on the ground only.

What would cause the Anti-ice triangle on the Bleed SD to turn amber?

- Valve is open and air pressure low or high | - Valve is open on the ground for >10sec

What does the engine identification number mean when its amber?

The engine N2 is below idle

What does the APU Bleed valve and line green on SD page mean?

APU MASTER sw is ON

APU indication on SD page -green line with amber crossline valve pic?

APU MASTER sw is ON APU valve is fully closed APU BLEED sw is ON for more than 10sec

Is APU bleed permitted for Wing Anti-ice?

NO!