Pneumatics

Question 1

What is ECS?

Answer 1

Environmental control system

Question 2

What is BAS?

Answer 2

Bleed air system

Question 3

Does bleed air use high or low pressure compressor ports? What are they called?

Answer 3

Both
Low pressure P2.2 P2.7
High pressure P3.0

Question 4

What regulates which bleed air port is used? Ie when high pressure is used and when low pressure is used?

Answer 4

The Electronic Control Unit together with power lever position

Question 5

At high power settings which bleed air supply is used? And at low pressure setting which bleed air is used?

Answer 5

High power = low pressure bleed air
Low power = high pressure P3.0

Question 6

What does the ECU do?

Answer 6

The interface between ECS control panel and the Bleed Air system components

Question 7

What is the redundancy for the ECU?

Answer 7

Digital and analogue control channels

Question 8

What do the digital channels control?

Answer 8

High pressure shutoff valve (HPSOV)
P2.2 Shutoff valves
Flow control shutoff valves (FCSOV)

Question 9

If a digital channel fails what happens?

Answer 9

The ECU analogue channel will take control

Question 10

After a failure of the digital control and the analogue takes over what can it control?

Answer 10

Low press bleed air operation

Question 11

What valve will close when under analogue control?

Answer 11

High pressure shutoff valve

Question 12

Turning the bleed air switch on enables operation of what valve?

Answer 12

Nacelle Flow Control Shutoff Valve (FCSOV) and P2.2

Question 13

Is bleed air available if selected OFF for de ice?

Answer 13

Yes

Question 14

What do the MIN, NORM and MAX cause the ECU to do?

Answer 14

To modulate bleed air by controlling the nacelle flow control shut off valves (FCSOVs)

Question 15

Does the MIN NORM MAX selector affect APU bleed air flow?

Answer 15

No

Question 16

1 or 2 BLEED HOT caution light cause and what auto happens?

Answer 16

Supply duct more than 349 degrees Celsius
The ECU closes the HPSOV and the FCSOV until the temperature returns to normal

Question 17

Do the HPSOV AND FCSOV fail open or closed?

Answer 17

Fail closed but will still allow bleed air to be supplied to the de icing

Question 18

When will bleed air default to min regardless of the switch position?

Answer 18

A bleed hot caution light
A bleed switch is off
Or from an engine shutdown

Question 19

If the analog and digital channels of the ECU fail on one side will the bleed hot caution light illuminate?

Answer 19

No

Question 20

With a failure of both left digital and analogue ECU channels, the #1 BLEED HOT caution light is ?

Answer 20

Unable to illuminate if a triggering condition exists

Question 21

The BLEED selector knob (MIN/NORM/MAX) allows regulation of bleed air flow through the ECS by ?

Answer 21

Controlling the Nacelle Flow Control Shutoff Valves (FCSOV)

Question 22

For the APU to supply bleed air ?

Answer 22

The #1 and #2 BLEED switches must be selected off

Question 23

The bleed air switches on the overhead panel control operation of their associated ?

Answer 23

Nacelle flow control shutoff valve (FCSOV)

Question 24

When the Environmental Control System ECU is under analogue control ?

Answer 24

The high pressure shutoff valve (HPSOV) will default to closed

Question 25

When an over temperature condition is experienced, the associated bleed air system will ?

Answer 25

Become operational when the temperature returns to the normal range

Question 26

If the #1 BLEED HOT light illuminates during flight and continuously remains illuminated the likely cause is ?

Answer 26

Either an over-pressure condition or duct leak being detected

Question 27

At high power settings, bleed air to the Environmental Control System and subsystems are supplied by ?

Answer 27

The low pressure port

Question 28

Bleed air for the Environmental Control System is provided by ?

Answer 28

The low pressure (P2.7) and high pressure (P3.0) ports

Question 29

For the high stage pre-cooler to be operational ?

Answer 29

The P2.2 Shutoff Valve (SOV) must be open