Pneumatic, AC, Pressurization Flashcards
With the destination altitude below 7850’ when does the CABIN ALTITUDE CAS illuminate?
Caution at 8500’
Warning at 9400’
Flying into Telluride(KTEX) the CABIN ALTITUDE WARNING HIGH (A) CAS illuminates. How does this affect the CABIN ALTITUDE (C) and (W)?
Increases caution to Field elevation +650’/ Increases warning to Field Elevation +1550’.
What is the IASC and how many are there?
Integrated Air System Controller –
controls all pneumatics
(Environmental, Anti-ice, and Leak monitoring)
(2 controllers each with 2 channels)
How many outflow valves are there?
1
Where is the outflow valve located.
Below the right wing leading edge, Behind right landing light.
How is the outflow valve opened and closed?
Electrically by servo motors.
How many safety valves are installed and where are they located?
Two on the aft pressure bulkhead
What is the function of the safety valves?
To provide overpressure and negative pressure relief
Do the safety valves require electrical power to operate?
No, they are pneumatically operated and spring loaded closed.
Does the environmental system use IP air or HP air?
IP (Intermediate Pressure) …regulated to ~ 50 psi
Most valves in the bleed and air conditioning system are controlled and actuated by?
Electrically controlled
Pneumatically actuated
What two valves are electrically actuated?
Outflow valve and avionics cooling valve
What does the Ozone Converter do?
Converts the Ozone from the IP bleed air into O2 to combat fatigue and dehydration
When the START switch is selected, what happens to the Flow Control Valves?
They automatically close to shut down the air conditioning system allocating all bleed air to the Starter(ATS)
When does the ditching switch become active?
Below 15000’ the outflow valve opens on a depressurizing schedule.
When pressurization delta P is 0, then the outflow valve
closes to prevent water from entering.
What does Ram air do?
Provides cooling air to the air heat exchangers and for cabin ventilation at low altitudes(unpressurized <10000)
(if the pack and trim air fail or unpressurized flight is required.)
Is the pack cold or hot air?
Trim air?
Hot air.
Pack air -Cold air.
Trim air-Hot air.
Pressing the Emer. Depress switch does what?
(MAN/AUTO)
Cabin depressurizes at:
2500fpm to 14000 in MAN mode,
3000fpm to 14500 in AUTO mode or aircraft altitude which ever is lower.
How is temp controlled in “Auto”?
Ventilated temp sensors in the cockpit and cabin input to the IASC’s to regulate set temperature.
How is temp controlled in “Manual”?
Direct control through the IASC’s to regulate the temperature.
The temperature “Pull up/Pull down works under what conditions?
APU or Pneumatic cart, Air source = Normal, Temp mode = AUTO, main cabin door not closed, and more
than 10* difference between selected and indicated temperature.
How many modes of pressurization operation are there?
3 Total modes
2 in “Auto” through the IASC’s
1 in “Manual” direct control of outflow valve via rate knob (max. 3000 fpm)
Where do you find “X-Bleed”/ “External Air Cart” start procedures?
QRH Volume 1 – Supplemental Section
How do you set landing altitude manually while in Auto Press mode?
Landing alt outer knob to manual and inner knob to select alt in 20 ft increments (cyan indicator)
Explain the takeoff and return to base sequence for pressurization.
When the aircraft leaves the ground, the takeoff sequence is initiated. The system will maintain the
pre−pressurization cabin altitude of 300 ft below field elevation until the aircraft reaches:
6,000 ft mean sea level (MSL) or differential from takeoff,
or
10 minutes has elapsed.
If a descent is initiated, the cabin altitude will descend to the takeoff altitude and the landing field elevation does not have to
be reset.
