Pneumatic system

Question 1

Which failure is the bleed system cause ECAM warning?

Answer 1

• Overheat
• Overpressure
• Leakage
• Discontinuity: Valve position disagree with command

Question 2

How does the bleed pressure regulation work?

Answer 2

The bleed valve, which is downstream of the junction of HP and IP ducting, acts as shut off and pressure regulating valve

Question 3

How does bleed temperature regulation work?

Answer 3

A precooler downstream of the bleed valve regulates the temp of bleed air.
Precooler is an air to air heat exchanger that use cooling air from engine fan to regulate the temp ≈ 200⁰C.

Question 4

Which systems or components are supllied by high pressure air?

Answer 4

• Air conditioning
• Water tank pressurization
• Hydraulic reservoir pressurization
• Wing anti ice
• Engine starter
• Fuel inerting system
• Cargo heating

Question 5

Pneumatic system operation is controlled and monitered by….

Answer 5

Two Bleed Monitoring Computers

(BMC)

Question 6

What are high pressure air source?

Answer 6

• Engine
• APU
• Ground unit (HP and LP)

Question 7

How does a leak detection system work?

Answer 7

It detecs any overheating in the vincinity of hot air duct

One loop system for APU and pylon
Two loop system for wing.To activate a wing leak signal, two loop must detect the leak or one loop if the other one is inoperative

Question 8

What is the function of crossbleed valve?

Answer 8

Allows the air supply systems of two engines to be isolated or interconnected

Question 9

What occurs if one BMC fails?

Bleed Monitoring Computer

Answer 9

The other one take over most of the function
* Lost bleed valve auto close function (related side)
* Lost leak warning function (related side)
* Lost the associated FAULT light on AIR COND panel (CEO only)

Question 10

On what ECAM page you will get information abt PNEUMATIC system?

Answer 10

BLEED page

Question 11

How does APU bleed valve work?

Answer 11

APU bleed valve operate as a shut off valve to control APU bleed air. It is electrically controlled and pneumatically operated

Question 12

What does the amber “FAULT” light in the APU BLEED pb indicate?

Answer 12

APU bleed leak

Question 13

What does the amber “FAULT” light in the ENG BLEED pb indicate?

Answer 13

• Overpressure
• Overheat
• Wing or Pylon Leak
• Bleed valve not close during engine start or APU bleed ON

Question 14

What occurs if BMC 1 fail?

Bleed Monitoring Computer

Answer 14

• Lost auto close function of engine bleed valve 1 and APU bleed valve
• Lost leak warning function of engine 1 and APU
• Lost “FAULT” light of engine bleed pb and APU bleed pb (CEO only).

Question 15

When will bleed valve auto close?

Answer 15

• During engine start
• APU bleed ON
• ENG FIRE pb pushed
• Ditching pb pushed
• Overpressure
• Overheat
• Leak

Question 16

When will APU bleed valve auto close

Answer 16

• APU leak
• Left wing leak
• Pylon 1 leak

(except when engine start)

Question 17

What logic control the X-bleed when X-bleed in auto?

Answer 17

• X-bleed open when APU bleed valve open
• X-bleed close when APU bleed valve close or when wing, pylon, APU leak

(Except during engine start)

Question 18

If APU is running, is it necessary to manually select APU BLEED OFF prior to APU shutdown?

Answer 18

NO

Question 19

On ECAM BLEED page, how can you tell if GND HP air supply is connected?

Ground High Pressure air

Answer 19

The GND unit temp and press are indicated on the ECAM BLEED PRECOLLER 1

Question 20

How GND LP air is supplied to aircraft?

Ground Low Pressure air

Answer 20

The air is supplied direct to mixture unit

Question 21

If the engine bleed air in-flight is too low, what will occur?

Answer 21

Engine speed is auto increased to provide adequate bleed air pressure

Question 22

After enigne start with APU bleed ON, what source is supplying bleed air to the packs?

Answer 22

APU bleed

Question 23

Can external HP source be used for air conditioning?

Answer 23

Maybe

Question 24

Which part of the engine did the pneumatic system take air from?

Answer 24

Normally from intermediate pressure stage (IP) of engine HP compressure.
At low speed when temp and press of IP are too low, air is drawn from HP stage.

Question 25

Can IP and HP stage supply bleed air at the same time?

Answer 25

NO

Question 26

Can BLEED valve of engine 2 open while APU bleed ON

Answer 26

Yes, when X-bleed is closed

Question 27

How many motors are controlling the X-bleed valve?

Answer 27

Two electric motors, one for manual, one for automatic

Question 28

When will PRECOOLER INLET PRESSURE indicated amber?

Answer 28

Below 4 psi or abv 57-60 psi

Question 29

What is normal range of PRECOOLER OUTLET TEMP?

Answer 29

Abv 150⁰C and not exceeds - 290⁰C for 5s - 270⁰C for 15s - 257⁰C for 55s

Question 30

How do you know LP unit has been disconected from A/C ?

Answer 30

Check there is no air coming from the air cond vent