PNEUMATICS, AIR CONDITIONING, AND PRESSURIZATION (ASM) Flashcards
Where does the pneumatic system get air from
Engine compression stage
APU
Ground source
When is the 14th stage used
Low thrust
Engine cross bleed start
Anti-Ice operations
How many ECU are there
2 ECU
What does the left ECU control
Cockpit
What does the right ECU control
Cabin
What distributes the air
The gasper system
What happens if both ECU fail
Ram Air Inlets open
Purpose of recirculation fans
2 electrical fans mix fresh air for passenger comfort
Where does the ECU get air from
Bleed air from pneumatic system
Where is pressure from the ECU regulated by
The pack valve
After pack valve where does the airflow go
Divided into 2 lines, a cold air that goes through air cycle machine. Hot air bypasses air cycle machine.
What happens to air in the Air Cycle Machine
Cooled in primary heat exchanger, then goes through secondary heat exchanger where is cooled again.
What controls cabin temperature in AUTO MODE
Controlled by Digital Controller
What controls cabin temperature in MANUAL MODE
Temperature control module
Where does the pressurization system receive static pressure from
The static ports
Purpose for pressurization pressure systems
For overpressure and negative pressure relief functions
What controls the pressurization in automatic mode
The digital controller
How do the outflow valves work in automatic mode
The pneumatic outflow valve is slaved to the electropneumatic outlfow valve
How is Theoretical Cabin Altitude calculated
So that maximum cabin differential pressure (7.8PSI) is reached at lowest possible airplane altitude
When does the automatic pressurization sequence on the ground occure
Plane on ground, engine 1 thrust lever set to THRUST SET
When does automatic pressurization takeoff sequence begin
Initiated once airplane leaves ground
When does automatic pressurization takeoff sequence end
Until theoretical cabin altitude is greater than actual cabin altitude or 15 minutes (whichever is first)
When does automatic de-pressurization on ground occur
On ground, engine 1 thrust lever idle
To avoid pressure bump during de-pressurization
Landing altitude -300 feet
What is de-pressurization controlled at
Rate of 650 fpm
What valve operates during manual mode
Only the pneumatic outflow valve (electropneumatic valve stays closed)
When do the exhaust fans and shutoff valves open in the forward electronic bay
Once temperatures reach 75ºF
When do the exhaust fans and shutoff valves close in the forward electronic bay
Once temperatures drop below 66ºF
How is the rear electronic bay cooled
Door closed: Conditioned air from cabin
On ground: Gasper fans
How is the baggage compartment ventilated
Recirculation fan
