Pneumatics Flashcards
How is a leak detected in the cowls
By a pressure transducer
What is a APU interlock protection
Prevents APU from supplying air
If engine bleed source is open
AILC?
Anti-ice and leak detection controller
What does the AILC provide?
EICAS msgs and system control of the bleed air leak detection system
Wing anti-ice is divided into how many sections
Four loops
L/R FUSELAGE LOOPS
L/R WING LOOPS
How are the leading edges heated
Hot bleed air from the duct is released through piccolo tubes
What detects failures in wing anti-ice ducting
Dual loops
And
A skin temperature sensor in wing leading edge
ACSC ( air-conditioning system controller) provides what during starts?
Isol valve opens/closes automatically during starts
How many zones is the pneumatic system divided into
5
L BLEED R BLEED L COWL R COWL WING ANTI ICE
Low pressure air?
High pressure air?
6th stage
10th stage
What’s manages the distribution of bleed air?
2 ACSC’s
Air conditioning system controllers
APPCH BIT … Landing
When do bleeds switch from engine to APU if bleeds closed are needed for landing
APPCH BIT
Either engine available
FLAPS greater then 20 degrees
Or
Ldg gear down
What does AILC(anti-ice and leak detection controller) do. If leak is detected
Sends signal to close valves to isolate system
only for leaks not overheat.. Wing overheat
APPCH BIT … Takeoff
When do bleeds transfer from APU to the engines on take off if bleeds closed needed
Landing gear up
AND
flaps 20 or less
Tl out of toga
Does anything close automatically for a wing overheat
No
What prevents compressor surge for the APU
Surge control valve
What monitors the bleed system for leaks
AILC anti-ice in leak detection controller
Pneumatically operated aircraft systems include:
Engine starting
Cowl and wing anti-ice
Air-conditioning and pressurization
- managed by two air conditioning system controllers(ACSC)
Test
The ACSC Will open or close the HPV depending on the bleed air manifold pressure and aircraft system requirements
What’s modulates the APU bleed air to the load control valve
ECU
TEST
BLEED MISCONFIG. amber
Indicates on impossible bleed configuration in manual mode
The bleed air leak detection system monitors
The pneumatic and anti-ice ducting for high temperatures associated with the bleed air leakage
EICAS Messages and system control of the bleed air leak detection system is provided by
On anti-ice and leak detection controller
AILC
The bleed air leak detection system is divided into five zones
Left and right bleed zone
Left and right, cowl anti-ice zones when anti-ice zone.
( when anti-ice zone is subdivided into four loops… Left and right fuselage loops, left and right wing loops)
The wing anti-ice loops ducting is encased in a protective cover, if a leak occurs …
Holes in the protective cover direct the hot bleed air towards the sensing loops
The cowl anti-ice ducts located in the engine pylons consists of
Inner and outer ducts
Bleed Air For anti-icing travels through the inner duct
The area between the inner and outer duct is monitored by a pressure transducer
The pneumatic system is supplied bleed air pressure from
The engine compressors
For the APU compressor
Manifold pressure is regulated to
45 PSI by the pressure regulating shut off valve(PRSOV)
Maximum altitude for engine starting with the APU
21000
Maximum altitude for APU bleed air
25000
Engines supply high or low pressure bleed air depending on
The high pressure valve(HPV)
What manages the distribution of bleed air?
Two independent air conditioning system controllers ..ACSCs
ACSC1 controls?
ACSC2 controls?
1… Left HPV and left engine bleed valve
APU LCV
Isolation valve
2… Right HPV and right engine bleed valve
PRSOV Is shown in two places
ECS synoptic page
Anti-ice synoptic page
What controls the isolation valve
ACSC
What provides interlock protection
ACSC
Prevents APUfrom supplying bleeder if any engine bleed source is open
What “modulates “ the APU LCV
The electronic control unit ECU
What is used for bleed air leak detection in the aft equipment be fuselage and wing
Dual heat sensing loops
What provides ice detection on the wing outermost slats
Only temperature sensors
Engines supply high or low pressure bleed air depending on
The high pressure valve(HPV)
What manages the distribution of bleed air?
Two independent air conditioning system controllers ..ACSCs
ACSC1 controls?
ACSC2 controls?
1… Left HPV and left engine bleed valve
APU LCV
Isolation valve
2… Right HPV and right engine bleed valve
PRSOV Is shown in two places
ECS synoptic page
Anti-ice synoptic page
What controls the isolation valve
ACSC
What provides interlock protection
ACSC
Prevents APUfrom supplying bleeder if any engine bleed source is open
What “modulates “ the APU LCV
The electronic control unit ECU
What is used for bleed air leak detection in the aft equipment bay fuselage and wing
Dual heat sensing loops
What provides ice detection on the wing outermost slats
Only temperature sensors
What shuts down pack during overtemp condition?
ACSC
Failure of a single loop is indicated by?
DUCT MON FAULT status
Or
WING A/I FAULT status
The bleed air manifold is divided into two sections by the?
Isolation valve
The left side of the bleed air manifold is pressurized by?
Right side?
Left side? Pressurized by external air source APU or the left engine
Right side? Pressurized by the right engine
(divided by the isolation valve)
Bleed valves fail?
Closed
What stage ”normally “ Provides air to operate the systems?
6 th stage
10 stage opens when the system demands exceed the capability of the six stage
Are there EICAS indications for the HPV operation?
No.. 18-4 pneumatics
APU LCV is fail safe?
Closed
Does manually selecting. The isolation valve open or closed override the systems protective features?
No
The active channel assignment of the AC SC is automatically switched?
Daily
18-6
If taxiing with the APU on And wing and or Cowl anti-ice is selected, What will happen
the ACSC Will command the APU LCV closed and the bleed valves open
18-8
If the APU is manually selected as the beed source And anti-ice is selected on?
apu lcv remains open
BLEED MISCONFIG
18-8
What opens to start the flow of 10th stage air until the sixth stage repressurizes?
HPV. High pressure valve
With ACSC number one working, What does number 2
Control?
Right PRSOV
right
HPV
How many zones are monitored by the bleed air leak detection system?
5
The AILC continuously checks ??
cowl anti icing ducts
Wingbanti icing ducts
The Wings leading edges bleed air leak detection is provided by Dual loops and??
Temperature sensors
Where is the bleed air Manifold located
In the engine pylons and aft equipment bay
Divided into two sections by the isolation valve
Are there any indications of the HPV operation on the EICAS?
No!! 18-4 ch 18 pneumatics 6/8/20
Just the PRSOV
Active channel assignment for the ACSC’s is automatically switched?
Daily. 18-6 ch 8 pneumatic 6/8/20
When do the bleeds transfer from the APU back to the engines after takeoff with the APU operating?
Landing gear up and flaps 20 or less …
Thrust levers out of takeoff detent
18-8 ch8Pneumatics6/8/20
If landing with the APU operating for bleed air .. when will the bleeds switch from the engines to the APU?
Flaps greater than 20
Or
Landing gear down
18/9 chapter 8 pneumatics 6/8/20
Regarding the bleed air leak detection system how many dual sensing loops must detect a leak before a EICAS messages posted?
Both loops Must detect a leak before a message is posted
18-11 Chapter 8 pneumatics
The APU LCV is controlled by?
The ECU
