Air/Pneumatic System Flashcards
What sources can supply the pneumatic system with pressurized air?
The 6th or 10th stage compressor sections off the engines, APU or a external ground air source
What is the function of the Air Conditioning System Controller? (ACSC)
Bleed source selection, Valve operation, air distribution
Where is the Engine start external ground air connector?
After left side of the fuselage
Where is the external ground air pressure (high pressure) monitored from the cockpit?
ECS Synoptic Page
What is the function of the Engine Bleed Valve (PRSOV)?
Limits and regulates the discharge pressure from the engine to 45psi ±3 psi
How can the pilot manually close the bleed valves?
By using the manual portion of the Bleed Air Control Panel
What is the function of the high pressure valve (HPV)?
To supply the 10th stage pressure when the system demands are greater than that of the 6th stage bleed air
What is the function of the APU LCV?
It opens to provide bleed air for ECS and engine starts and modulates to control the amount of bleed air taken from the APU
What unit controls the APU LCV?
The APU ECU
What side of the bleed manifold does the APU supply bleed air?
The left side
What is the function of the Isolation Valve?
To connect the left and right sides of the bleed manifold?
When does the Isolation Valve automatically open?
During engine starts, and when the APU LCV is opened
When does the Isolation Valve automatically close?
During transfer of the bleeds from the APU to the engines
How can the pilot manually operate the Isolation Valve?
Using the switches on the Bleed Air Control Panel
What bleed source will supply the bleed air manifold on the ground with the APU and engines running and the bleed valve selector in the auto mode?
APU
When does the ACSC switch from the APU to the engines as a bleed source after departure?
When the thrust levers are retarded from the takeoff detent, flaps up and gear up (20 sec)
When does the ACSC switch from the engines to the APU as a bleed source during approach?
When the flaps are greater than 20° or the gear is down (20 sec)
What will occur if the APU is supplying bleed air to the manifold and either cowl or the wing anti-ice is selected on with both engines operating?
The ACSC will close the APU LCV and transfer the bleeds to the engines
What will occur if the APU is supplying bleed air and the wing or cowl anti-ice is selected on with the engines shutdown
The ACSC will close the APU LCV, the manifold will depressurize, and the BLEED MISCONFIG caution message will appear
What happens when the START switchlight is pressed
Isolation Valve opens, both AC Packs close, the Start valve opens, and the Air Turbine Starter engages
What is the function of the Bleed Air Leak Detection System?
Monitors the bleed air and anti-ice ducts for leaks
What is the function of the Anti-Ice Leak Detection Controller?
Dual channel to monitor the anti-ice and bleed air ducts and the integrity of both loops of the detections system
What happens when the pilot selects close on the Bleed Air Control Panel?
It closes all the valves except for the external air source
What happens when the pilot selects “Manual” on the Bleed Air Control Panel?
It allows the pilot to control the valve position with the exception of the ACSC interlocks and system logic, and engine starting sequence
What is the function of the Environmental Control System (ECS)?
Provide conditioned air to the cockpit and cabin
Where are the air conditioning packs?
Aft Equipment Bay
What part of the aircraft does Pack 2 supply?
Cabin and Aft Cargo bay
What part of the aircraft does Pack 1 supply?
Cockpit
How is the Temperature Control Valve regulated from the cockpit
By twisting the Cockpit or Cabin rotary selector on the Air Conditioning Panel
What is the function of the Ram Air Intake Scoop and where is its location?
It provides air to cross the heat exchangers, or provide ventilation to the cockpit and cabin in the event of both packs failing, and is located at the base of the vertical fin
Where is the Ram Air exhausted after passing through the heat exchangers?
Out through exhaust vent on the left and right sides of the aft fuselage
If there is no ram air available, how are the heat exchangers cooled?
There is a fan mechanically connected to the Air Cycle Machine that draws air through the duct for cooling
What is the function of the low pressure Environmental Control System air-ground connector?
To provide preconditioned air into the mixing manifold for distribution
What is the function and location of the Recirculation Fans?
They are located in the mixing manifold recirculation inlet ducts and to draw air from the passenger compartment to the mixing manifold
How are the CRT’s cooled and ventilated?
Air from the cockpit air conditioning duct and the 2 display cooling fans
What is the function of the GND ALT position of the DSPLY FAN selector located on the center pedestal?
If allows the fan normally used in flight to cool the CRT’s on the ground in the event the ground fan fails
What is the function of the STDBY position of the DSPLY FAN selector located on the center pedestal?
Power is removed from both fans
What is provided to cool the electronics in the avionics bay?
2 Avionics fans
What is the function of the Ground Valve?
It opens on the ground to allow the air that cools the CRT’s and the avionics bay to be dumped overboard, and also ensures that the aircraft is fully depressurized on the ground
When does the ground valve open and close?
It closes when the passenger and galley doors are closed, and opens with WOW at touchdown
How long is departure field elevation maintained after departure?
For 10 minutes above altitudes 6,000 above the takeoff field elevation
What is the function of the Pneumatic Safety Valves?
To provide overpressure and negative pressure relief
How can the pilots manually switch between CPC 1 and 2?
Press PRESS CONTROL switchlight twice
What is the Cabin Pressure Controller (CPC)
2 CPC’s control all the automatic pressurization process
What is the function and location of the outflow valve?
Located at the aft pressure bulkhead and controls the discharge of the air from the aircraft
How fast does the ground valve open if the EMER DEPRESS is pushed while on the ground?
2 seconds
What is the max altitude the cabin will go to if the EMER DEPRESS is pushed in flight?
14,500ft ±500 ft
