Pressurization, page 02-10-10 Flashcards
How is Pressurization achieved
by controlling the leakage rate through the 2 outflow valves
What does CPAM stand for?
Cabin Pressure Acquisition Module
What do the CPAM’s do
provide the data concentrator units (DCU’s) with pressurization data for display on the EICAS
What does an amber Cabin ALT mean
Cabin Alt is between 8500 and 10,000
Red Cabin ALT
Cabin exceeds 10,000 during low altitude airfield ops and 14,500 during high airfield ops
Red DIFF PRESS
Cabin Pressure differential exceeds 9.0
The Cabin Pressure Controller (CPC) receives input from what 4 things to control the outflow valves?
S3 Static port (Ambient Pressure), Cabin Pressurization Selector, Trust levers, and weight-on-wheels
If the Cabin Pressure Controler (CPC) fails what happens to the outflow valves
They go into isobaric hold mode and maintain existing cabin alt
What does an amber AUTO PRESS EICAS message mean
The CPC has failed. Should see a fault light on the cabin Press selector and FAIL annunciator on the PRESS CONT
Are the outflow valves spring loaded open or closed
spring-loaded closed
What provides the vacuum for the outflow valves
10th stage bleed air to jet pump which creates a venturi action
The outflow valves try to maintain diff pressure between what and what
0 and 8.8
What happens when the pressure in the fuselage reduces to -0.5
Outflow valves automatically open to equalize pressure
What happens when EMER DEPRESS is selected
An electrical signal commands the outflow valves to open
What does the FAULT light indicate on the Cabin Pressurization Panel (CPC)
That the Cabin Pressurization System has failed
Not including the Manual Mode on the CPC, how many different modes does the CPC have? and what are they?
(8) Ground mode, Pre-pressure mode, Takeoff, Flight, Flight abort, Landing, Touch and Go and High Altitude Airfield.
Describe Ground mode
Both outflow valves fully open for max ventilation
Describe Pre-Pressure mode
Thrust levers advanced to Takeoff cabin is pressurized to -150 to -200 feet below field elevation to eliminate pressure bumps
Describe Takeoff abort mode
Thrust levers are retarded during a rejected takeoff. Cabin climbs back to field elevation at 500 fpm for 20 seconds then the CPC goes into Ground mode
Flight mode
When the CPC receives weight of wheels signal it goes into a scheduled of pressurization. It will select either field elevation (landing) or scheduled rate which ever is higher.
With the auto RATE knob at the “pip” mark what will the cabin climb and descend at?
500 foot up and 300 foot down
Describe Flight Abort Mode
CPC drives the cab in to takeoff field elevation if: Less than 10 min elapsed since takeoff; Aircraft has climbed less than 6000 feet; Descent is detected
Describe Landing Mode
CPC receives weight on wheels signal, thrust levers at idle, after 60 sec the CPC goes into Ground Mode
Describe Touch and Go Mode
On touch down system goes into Landing Mode as thrust levers are advanced the system will go into schedule pre-press mode
