Pneumatics Flashcards
What compressor stage is HP air taken from?
6th
What compressor stage does P3 air come from?
6th
What compressor stage does P2.5 air come from?
5th
How is the HP valve controlled
Electrically
How are HP valve operated?
Pbeumatically
What are the reasons the HP valve would automatically close?
Bleed air over temp (288 deg C) Bleed air over pressure (76 PSI) Fire handle is pulled Engine is shut down Main DC bus power is lost
➢What are the reasons the LP valve would automatically close?
Bleed air over temp (288 C)
Bleed air over pressure downstream of valve (43 PSI)
Fire handle is pulled
Air conditioning pack over temps (225 C)
Air conditioning duct over temps (82 C)
What does a BLD CLOSED light indicate?
Bleed valve is closed
➢What does a BLD FAULT light indicate?
Bleed air temperature excessive (>288 C)
Regulated pressure excessive (>43 PSI)
Valve fails to close when signaled to close
➢What does a HP HIGH light indicate?
Valve fails to close when signaled to close
➢Are the pneumatic systems interconnected?
Yes, cross valve
When can cross valve be used?
On the ground only
What is required for the XVALVEto open?
One engine bleed valve closed
How is the XVALVE controlled?
Electrically
How is XVALVE operated?
Pneumatically
What does a XVALVE OPEN light indicate?
Cross valve open
What does a RECIRC light indicate?
Recirculation fan underspeeds
Does manual mode provide temp limiting?
No, only auto mode does
➢In manual mode how long does it take to move the control valve full travel ?
6 to 8 seconds
What does a AVIONICS VENT light indicate?
Fault occurs in the avionics vent fan
When is the only time HP air is automatically provided?
When LP is insufficient (Ng
➢If electrical power fails what position will the LP valve be in?
Open
➢If electrical power fails what position will the HP valve be in?
Closed
On the air conditioning panel an amber DUCT OV TEMP indicates?
ACM compressor discharge overheating
Distribution duct over heating
What other valve automatically closes with this light?
Corresponding engine bleed valve
➢What cools the Recirc fan?
Bleed air
Will the AIRCOND master caution activate with a RECIRC amber light?
No
The temperature control knobs sets cabin temp to what range in the AUTO mode?
18 to 29 C
➢Is the RECIRC fan temperature protected?
Yes, thermal cutoff will turn off till it cools then allows fan to turn on
What does the CABIN PRESS light indicate?
Cabin altitude above 10,000 ft
Cabin pressure exceeds 7.5 PSI
What controls the outflow valves?
Electric and Pneumatic
In flight, activation of PRESS DUMP opens?
Primary outflow valve
What compressor stage is the LP air taken from?
5th
➢On ground, activation of PRESS DUMP?
Primary and secondary outflow valves fully open
The outflow valves limit negative pressure to?
-0.5 PSI
If vacuum pressure is lost, the outflow valves revert to?
Closed
➢In manual pressurization mode what position is the primary outflow valve in?
Closed
Where is the secondary outflow valve located?
Rear pressure bulkhead
What rate of cabin VSI does the detent on the auto controller provide?
500 fpm up and 300 fpm down
