Pressurization, page 02-10-10

Question 1

How is Pressurization achieved

Answer 1

by controlling the leakage rate through the 2 outflow valves

Question 2

What does CPAM stand for?

Answer 2

Cabin Pressure Acquisition Module

Question 3

What do the CPAM’s do

Answer 3

provide the data concentrator units (DCU’s) with pressurization data for display on the EICAS

Question 4

What does an amber Cabin ALT mean

Answer 4

Cabin Alt is between 8500 and 10,000

Question 5

Red Cabin ALT

Answer 5

Cabin exceeds 10,000 during low altitude airfield ops and 14,500 during high airfield ops

Question 6

Red DIFF PRESS

Answer 6

Cabin Pressure differential exceeds 9.0

Question 7

The Cabin Pressure Controller (CPC) receives input from what 4 things to control the outflow valves?

Answer 7

S3 Static port (Ambient Pressure), Cabin Pressurization Selector, Trust levers, and weight-on-wheels

Question 8

If the Cabin Pressure Controler (CPC) fails what happens to the outflow valves

Answer 8

They go into isobaric hold mode and maintain existing cabin alt

Question 9

What does an amber AUTO PRESS EICAS message mean

Answer 9

The CPC has failed. Should see a fault light on the cabin Press selector and FAIL annunciator on the PRESS CONT

Question 10

Are the outflow valves spring loaded open or closed

Answer 10

spring-loaded closed

Question 11

What provides the vacuum for the outflow valves

Answer 11

10th stage bleed air to jet pump which creates a venturi action

Question 12

The outflow valves try to maintain diff pressure between what and what

Answer 12

0 and 8.8

Question 13

What happens when the pressure in the fuselage reduces to -0.5

Answer 13

Outflow valves automatically open to equalize pressure

Question 14

What happens when EMER DEPRESS is selected

Answer 14

An electrical signal commands the outflow valves to open

Question 15

What does the FAULT light indicate on the Cabin Pressurization Panel (CPC)

Answer 15

That the Cabin Pressurization System has failed

Question 16

Not including the Manual Mode on the CPC, how many different modes does the CPC have? and what are they?

Answer 16

(8) Ground mode, Pre-pressure mode, Takeoff, Flight, Flight abort, Landing, Touch and Go and High Altitude Airfield.

Question 17

Describe Ground mode

Answer 17

Both outflow valves fully open for max ventilation

Question 18

Describe Pre-Pressure mode

Answer 18

Thrust levers advanced to Takeoff cabin is pressurized to -150 to -200 feet below field elevation to eliminate pressure bumps

Question 19

Describe Takeoff abort mode

Answer 19

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

Question 20

Flight mode

Answer 20

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.

Question 21

With the auto RATE knob at the “pip” mark what will the cabin climb and descend at?

Answer 21

500 foot up and 300 foot down

Question 22

Describe Flight Abort Mode

Answer 22

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

Question 23

Describe Landing Mode

Answer 23

CPC receives weight on wheels signal, thrust levers at idle, after 60 sec the CPC goes into Ground Mode

Question 24

Describe Touch and Go Mode

Answer 24

On touch down system goes into Landing Mode as thrust levers are advanced the system will go into schedule pre-press mode

Question 25

Describe High-Altitude Mode

Answer 25

8000 feet is the reference for the cabin. At landing and takeoff elevations of up to 14,000 feet the cabin will be allowed to climb to 8000 feet after takeoff (lower takeoff elevation) or driven down to 8000 feet after takeoff (higher than 8000). When descending out of 25,000 ft the cabin will be driven to the landing field elevation.

Question 26

The Press Cont (control) switch light on the CPC has two indications FAIL and MANUAL, what do they mean?

Answer 26

Manual light: manual mode has been selected. Fail light: CPC has failure