SAAB 340B Pneomatics Flashcards
What compressor stage is the LP air taken from?
5th
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 is the HP valve operated?
Pneumatically
What are the reasons the HP valve would automatically close?
Reason 1
Bleed air over temp (288 deg C)
What are the reasons the HP valve would automatically close?
Reason 2
Bleed air over pressure (76 PSI)
What are the reasons the HP valve would automatically close?
Reason 3
Fire handle is pulled
What are the reasons the HP valve would automatically close?
Reason 4
Engine is shut down
What are the reasons the HP valve would automatically close?
Reason 5
Main DC bus power is lost
What are the reasons the LP valve would automatically close?
Reason 6
Bleed air over temp (288 C)
What are the reasons the LP valve would automatically close?
Reason 7
Bleed air over pressure downstream of valve (43 PSI)
What are the reasons the LP valve would automatically close?
Reason 8
Fire handle is pulled - Air conditioning pack over temps (225 C)
What are the reasons the LP valve would automatically close?
Reason 9
Fire handle is pulled - 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?
1
Bleed air temperature excessive (>288 C)
What does a BLD FAULT light indicate?
2
Regulated pressure excessive (>43 PSI) - Valve fails to close when signaled too close
What does a HP HIGH light indicate?
Valve fails to close when signaled too close
How is HP air cooled?
Ram air heat exchanger, Precooler
Are the pneumatic systems interconnected?
Yes, cross valve
When can the cross valve be used?
On the ground only
What is required for the XVALVE to open?
One engine bleed valve closed
How is the XVALVE controlled?
Electrically
How is the XVALVE operated?
Pneumatically
What does a BLD AIR LEAK light indicate?
Bleed air leak is detected (excessive temp 205 C)
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?
6-8 seconds
What does a AVIONICS VENT light indicate?
Fault occurs in the avionics vent fan
What systems are operated by pneumatic air?
Air Conditioning, Pressurization, Boots
When is the only time HP air is automatically provided?
When LP is insufficient (Ng < 80%)
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?
18-29 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 feet - Cabin pressure exceeds 7.5 PSI
What controls the outflow valves?
Electric and Pneumatic
In flight, activation of PRESS DUMP opens?
Primary outflow valve
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
