Bleed Air : Pneumatic

Question 2

Which failure in the bleed system causes an ECAM warning?

Answer 2

Overpressure overtemperature and wing leak.

Question 3

How does the bleed pressure regulation work?

Answer 3

The bleed valve which is downstream of the junction of HP (high pressure) and IP (intermediate pressure) ducting acts as a shut-off and pressure regulating valve. It maintains delivery pressure at 45 +/- 5 psi.

Question 4

How does the bleed temperature regulation work?

Answer 4

A precooler downstream of the bleed valve regulates the temperature of the bleed air. The precooler is an air-to air heat exchanger that uses cooling air bleed from the engine fan to regulate the temperature to approximately 200°C.

Question 5

Which systems or components are supplied by high pressure air?

Answer 5

Air conditioning engine starting wing anti-ice water pressurization and hydraulic reservoir pressurization.

Question 6

Pneumatic system operation is controlled and monitored by…

Answer 6

Two Bleed Monitoring Computers (BMC).

Question 7

What are the high pressure air sources?

Answer 7

Engine bleed systems APU load compressor and HP ground connection.

Question 8

What is the function of the crossbleed valve?

Answer 8

The crossbleed valve on the crossbleed duct allows the air supply systems of two engines to be isolated or interconnected.

Question 9

What occurs if one Bleed Monitoring Computer (BMC) fails?

Answer 9

If one BMC fails the other one takes over most of the monitoring functions.

Question 10

On which ECAM page you will get information about the PNEUMATIC system?

Answer 10

BLEED page.

Question 11

How does the APU bleed valve work?

Answer 11

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

Question 12

How does the bleed leak detection work?

Answer 12

Leak detection loops detect any overheating near the hot air ducts in the fuselage pylons and wings. For the pylon and APU the sensing elements are tied to form a single loop and for the wing a double loop.

Question 13

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

Answer 13

Bleed leak (APU Bleed valve closes)

Question 14

What logic control the X-Bleed valve when the X-BLEED switch is in auto?

Answer 14

• When APU valve is open, the x-bleed valve is open
• When APU bleed valve is closed, the x-bleed valve is closed
• X-bleed also closes for wing, pylon, or APU duct leak (Except during engine start)

Question 15

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

Answer 15

No. When the APU MASTER sw is selected OFF, the bleed air valve is closed and the APU is allowed to cool prior to shutdown

Question 16

The pneumatic system is monitored and controlled by?

Answer 16

2 Bleed Monitored Computers (BMC)

Question 17

If one BMC fails, can the other take over?

Answer 17

Yes, they are interconnected. If one BMC fails:

• APU and ENG 1 leak detections are not monitored
• ECAM APU BLEED LEAK warning is lost

Question 18

On the ECAM Bleed page, how do you tell if the GND HP air supply is connected?

Answer 18

The GND unit temperature and pressure are indicated on the ECAM BLEED PRECOOLER 1

Question 19

How can you tell if the GND LP air supply is removed before selecting the APU BLEED pushbutton to on?

Answer 19

Turn off the CAB FANS pushbutton, open the air vent on the instrument panel and confirm no airflow.

Question 20

What flow rate is automatically selected when APU bleed air is in use or during single pack operation?

Answer 20

HI

Question 21

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

Answer 21

Engine speed is automatically increased to provide adequate bleed air pressure

Question 22

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

Answer 22

APU Bleed

Question 23

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

Answer 23

An APU bleed leak