A320 Lounge Pneumatics

Question 1

What does the pneumatic system provide air for (in terms of systems)

Answer 1

Air conditioning
Engine starting
WAI
Water pressurisation
Hydraulic reservoir pressurisation

Question 2

What are the sources of the high pressure air?

Answer 2

Engine bleed
APU load compressor
HP ground connection

Question 3

What are the computers associated with the pneumatic system?

Answer 3

BMCs (Bleed Monitoring Computers)

They are monitoring computers, not management computers

Question 4

How many BMCs are there?

Answer 4

2

Question 5

How are the BMCs involved in bleed demand?

Answer 5

They’re not really - they simply monitor the bleed system, and electrically shut valves if there is an issue

Question 6

What do the BMCs do?

Answer 6

Monitor bleed pressure, temperature and valve positions

They can electrically shut valves if:

Pressure and temperature limits exceeded
Leaks are detected
APU bleed valve malfunctions
Pilot operates the engine fire pb or bleed pb

Question 7

Which computers does the BMC send information to?

Answer 7

FWCs and SDACs

They also send information to the push button fault lights

Question 8

What does BMC 1 look at?

Answer 8

Temperature and pressure in ENG1,

In a CEO, it will also monitor temperature and pressure in ENG2, but in a NEO, it will only look at pressure in ENG2

Question 9

What can BMC1 operate?

Answer 9

It can only control its own side.

BMC1 can control the ENG1 bleed valve, the x bleed valve and the APU bleed valve

Question 10

Can BMC2 operate the APU bleed valve?

Answer 10

No

BMC1 can, although this is through the ECB

Question 11

What is the target pressure for the ENG bleed valve to create downstream?

Answer 11

CEO 45 psi +/-5

NEO if both engines operating
42psi +/-3

If NEO single engine, 50psi +/-3

Question 12

What happens in normal conditions if the pressure demand from the intermediate stage isn’t being satisfied from the engine?

Answer 12

The HP stage will open, which is at a higher pressure. This tends to happen at low thrust and can be seen at the bottom of the ECAM page

Question 13

Which side of the X BLEED valve is the APU bleed connected?

Answer 13

Left

Question 14

Which side of the X BLEED valve is the HP ground air supply connected?

Answer 14

Left

Question 15

What is the target output temperature of the precooler (downstream of the BLEED valve)

Answer 15

200C

Question 16

How is the output temperature of the engine bleed regulated?

Answer 16

Air downstream of the BLEED valve is mixed with air from the fan stage of the engine (via a fan air valve) and mixed in a precooler

Question 17

Which side of the X BLEED valve do the hydraulic reservoirs take pressure?

Answer 17

Either side

Question 18

Why can’t APU bleed be used for WAI?

Answer 18

It isn’t strong enough to guarantee equal anti-icing on each wing

Question 19

What is the principle of the bleed leak detection?

Answer 19

Temperature is measured just outside the bleed system, and if this is abnormally high, the BMC assumes the cause of the high temperature is a bleed leak

Question 20

Will you get an ECAM caution with a failure of a BMC?

Answer 20

No

Question 21

Why in some bleed leak ECAM procedures is there a line “if not closed”?

Answer 21

Because a BMC may have failed, and the ECAM may have been generated from the offside BMC

Question 22

What is the box halfway up the ECAM BLEED page, which has pressure and temperature values in?

Answer 22

The precooler, with the input pressure and output temperature

Question 23

What is the valve immediately below the precooler on the ECAM BLEED page?

Answer 23

ENG BLEED valve

Question 24

What happens in flight if you turn on the APU BLEED?

Answer 24

The cross bleed valve opens, the APU bleed valve opens, and the two ENG BLEED valves close, enabling the entire bleed demand to be supplied from the APU