CRJ Systems > Pneumatics > Flashcards

Pneumatics Flashcards

(62 cards)

Study These Flashcards
1
Q

What does the pneumatic system of the aircraft provide?

A

High-temperature, high-pressure air for use by many of the aircraft’s other
systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the main components of the pneumatic system?

A

the pneumatic
system supplies bleed air for engine starting, cowl and wing anti-ice, air
conditioning, and pressurization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the primary source of bleed air for the pneumatic system?

A

sixth-stage bleed air port

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When is the tenth-stage bleed air port used?

A

in the event there is
insufficient pressure to accommodate the system’s demand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The pneumatic system supplies bleed air for:

A

Narration
The pneumatic system supplies bleed air for:
* engine starting,
* cowl anti-ice,
* wing anti-ice,
* air conditioning,
* and pressurization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What prevents the backflow of tenth-stage air into the sixth-stage bleed air
port?

A

A check valve prevents the backflow of tenth-stage air into the sixth-stage bleed air port

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What prevents the backflow of tenth-stage air into the sixth-stage bleed air
port?

A

Left and right side.
The sides are connected by an isolation valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the four sources of air available to the manifold?

A

Left and right
engines, the APU, and an external air inlet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What side does the apu supply bleed air to

A

left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where is the external air inlet located?

A

left aft side of the fuselage aft of
the aft cargo bay door

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is the isolation valve powered and controlled?

A

28v DC powered
valve that is controlled by the Air Conditioning System Controllers
(ACSCs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

A manual override lever on the ISO and PRSOV and high pressure valves allows

A

maintenance to lock the isolation valve in the desired position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

10.Air from either the 6th stage or the 10th stage port flows through a Pressure Regulating Shutoff Valve, or PRSOV.
This valve is also called the engine bleed valve. What is the purpose of the (PRSOV)?

A

To limit engine bleed air pressure and to shut off bleed air supply from the
associated engine if needed. It all depends on how fast the N2 speeds are

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is the bleed air valve controlled and activated?

A

Electrically controlled
and pneumatically activated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

12.What is the minimum air pressure required for the bleed air valve to
operate?

A

13 psi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

13.What happens to the bleed air valve when the associated engine is shut
down?

A

It will automatically shut down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The high-pressure valve controls the flow of bleed air from

A

the tenth-stage bleed air port

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

14.What controls the operation of the high-pressure valve?

A

The Air
Conditioning System Controller (ACSC). The high-pressure valve will automatically close in the event of a loss of pressure or power.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The high-pressure valve will automatically close under one of the following situations:

A
  • the associated engine bleed valve is closed,
  • upstream bleed air pressure is less than 13 psi,
  • a bleed air leak has been detected,
  • ACSC signal has been lost,
  • or the associated ENG FIRE PUSH switchlight has been pressed.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

APU bleed air power the system

A

The APU can be used to pressurize the pneumatic system through the APU Load Control Valve, or LCV.
APU bleed air is connected to the left side of the pneumatic system.
The APU load control valve is electrically controlled and pneumatically operate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

15.What protects the APU from reverse flow of pneumatic air?

A

the LCV
interlock system and a check valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

16.What signals the APU ECU to open the APU Load Control Valve?

A

ACSC when APU bleed air is required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

17.Under what conditions will the high-pressure valve automatically close?

A

The associated engine bleed valve is closed, upstream bleed air pressure
is less than 13 psi, a bleed air leak has been detected, ACSC signal has
been lost, or the associated ENG FIRE PUSH switch light has been
pressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

18.How is external pneumatic air supplied to the aircraft’s pneumatic system?

A

via an external pneumatic air cart through a one-way check valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
The bleed air valves should be open or closed with external air
closed when the ground cart is supplying the pneumatic system. This prevents the back flow of air into the engines.
26
19.What does the bleed air leak detection system monitor?
Various areas of the pneumatic system for any bleed air leaks
27
21.What are the zones monitored by the bleed air leak detection system?
left and right bleed zones, left and right cowl anti-ice zones, and wing anti-ice zone * engine pylons, * aft equipment bay, * anti-ice ducts in the aft equipment bay, * center fuselage section, * and wing leading edges
28
22.What happens if a leak is detected in the wing anti-ice ducting or piccolo tubes?
The EICAS will display an ANTI-ICE DUCT red warning message, along with an ANTI-ICE DUCT aural warning
29
Leading edge leak
The dual loop leak detection loop does not extend to the outboard end of slat three. Leak detection in this area is provided by an outboard skin temperature sensor. Should a leak occur in this area, the skin temperature would increase and trigger a leak warning
30
Bleed leak detection leaks
Each zone is monitored by a dual set of sensing elements running along the ducts. The sensing elements are mounted in parallel and form two loops designated loop A and loop B. Each loop is connected to an anti-ice and leak detection controller, or AILC. This controller has two channels designated A and B, and each loop is connected to its associated channel.
31
detection leak, bleed line condtruction
In order for the bleed leak system to operate properly, the bleed air ducts and the center fuselage anti-ice ducts are designed as a duct inside a protective outer sheath. This outer cover is pre-drilled with small holes so that if the inner ducting begins to leak, the outer cover will contain the hot air and only let it escape through the pre-drilled holes. The overheat detection loops are mounted on the outer cover, directly in-line with these holes.
32
23.How does the cowl anti-ice duct leak system detect leaks?
Via a pressure switch. The cowl anti-ice system is a double walled duct. Hot bleed air flows through the inner duct. If a leak occurs in the inner duct, then it will enter the outer duct. A pressure transducer detects the pressure increase and triggers the L or R COWL A/I DUCT red warning message and an aural ANTI-ICE DUCT warning will sound.
33
24.What manages the bleed air system?
Air Conditioning System Controllers (ACSCs) called ACSC 1 and 2. located in the avionics abby
34
25.What does ACSC 1 normally control?
The left engine bleed air valve and its associated high-pressure valve (ACSC 2 controls these 2 valves for the right engine), APU load control valve, and the isolation valve.
35
26.What happens in the event of a failure of ACSC 1?
Control of the APU LCV and the isolation valve will be transferred to ACSC 2
36
27.How is the active channel of each ACSC swapped?
Each ACSC has 2 channels, an active and a backup. The active channel is swapped on a daily basis
37
28.What mode is normally used to operate the bleed air system?
automatic mode. In this mode, the ACSC will position the high-pressure valve based on the: * sixth stage pressure, * pack inlet pressure, * demand from the air conditioning system, * and demand from the anti-ice system
38
30.What happens when the APU is running while the aircraft is on the ground?
the ACSC will select the APU as the source of bleed air
39
31.What does the ACSC prevent the APU from supplying pneumatic air to?
Anti ice. if slected the ACSC will shut the APU LCV to and open the engine bleed valve
40
Bleed valves knob closed on overhead panel
Placing the BLEED VALVES knob in the CLSD position closes the engine bleed air valves and the APU load control valve. This is the position that should be selected when external pneumatic air is supplied to the pneumatic system
41
Bleed valves knob manual on overhead panel
The MANUAL position enables the crew to manually control the bleed air system. When this position is selected, the ISOL switch and the bleed source knob are enabled.
42
ISOL switch ON on the overhead panel
The ISOL switch electrically opens or closes the bleed air isolation valve
43
32.What does the BLEED VALVES knob in the CLSD position do?
closes the engine bleed air valves and the APU load control valve (you will select this position when external pneumatic air is supplied to the pneumatic system)
44
35.What does the BLEED SOURCE knob control?
Controls the sources of bleed air (L engine, R engine, or APU)
45
36.What happens when the BLEED SOURCE knob is in the L ENG position?
left engine bleed valve opens if the engine is running, and the right engine bleed valve and APU LCV are closed
46
37.What happens when the BLEED SOURCE knob is in the R ENG position?
right engine bleed valve opens if the engine is running, and the left engine bleed valve and APU LCV are closed
47
38.What is the purpose of the manual override lever on the isolation valve?
Allows maintenance to lock the isolation valve in a desired position
48
What happens when the BLEED SOURCE knob is in APU
When the BLEED SOURCE knob is in the APU position, both engine bleed air valves close and the APU Load Control Valve opens if the APU is ready to supply bleed air.
49
If the APU is operating during the takeoff, the bleed air load will transfer automatically from the APU to the engine bleed air when the:
* thrust levers are out of the takeoff detent, * landing gear is up, * and flaps are 20 degrees or less. This transfer is accomplished automatically and takes approximately 20 seconds
50
APU Bleed Misconfig
In the manual mode, the crew could potentially select the APU as the bleed source while the cowl or wing anti-ice is selected ON. If this were the case, the APU load control valve would not automatically close. However, the wing anti-ice valves will not open and a BLEED MISCONFIG caution message would be displayed on the EICAS.
51
If the APU is operating during the approach, the APU load control valve will open and the engine bleed air valves will close when:
* the flaps are greater than 20 degrees, * or the landing gear is extended. This automatic transfer takes approximately 20 seconds.
52
39.What happens if the ACSC signals are lost?
The bleed air valves will fail closes
53
40.How does the bleed air leak detection system perform a loop continuity test? A
A loop continuity test is performed on each set of loops when the aircraft is initially powered and after each landing
54
41.What indication is given if a loop is open during the continuity test?
A DUCT MON FAULT white status message is displayed on the EICAS
55
42.How is the bleed air leak warning presented to the flight crew?
L or R BLEED DUCT red warning message
56
43.What does the BLEED MANUAL message on the ECS page indicate?
The bleed system is being operated in the manual mode
57
44.What happens if the APU is operating during takeoff?
The bleed air will transfer automatically from the APU to the engine bleed air once the thrust levers are out of the takeoff detent, the landing gear is up, and the flaps are 20 degrees or less
58
45.How long does the automatic transfer of bleed air load from the APU to the engine bleed air take?
20 seconds
59
46.What happens if the APU is operating during the approach?
The APU LCV will open and the bleed air valves will close when the flaps are greater than 20 degrees, or the landing gear is extended
60
47.How is the status of the pneumatic system displayed?
on the ECS and ANTI-ICE synoptic pages. Valve position is indicated by an inline or crossline bar. If a valve has failed in a particular position, it will be displayed in amber. The inline or crossline bar is removed completely removed from view in the event a valve does not go to the commanded position. Bleed air pressure is displayed in numerical format
61
EICAS external air indication
There are no symbols to indicate that an external pneumatic air cart is supplying the pneumatic system. The only indication is the ground cart pneumatic air pressure that is displayed on the ECS synoptic page.
62
Min psi for cross bleed engine start
42 psi
CRJ Systems
flashcards
Decks in class (28)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions