CABIN PRESS PANEL

Question 0

WHAT DOES THE MANUAL ALTITUDE FUNCTION DO?

Answer 0

MAN ALT – Controls pressurization in manual mode

UP/DN – Commands cabin altitude to climb or descend.

Question 1

WHAT DOES THE LANDING FIELD ELEVATION KNOB DO?

Answer 1

LDG ELEV – Sets destination airport altitude.

Question 2

WHAT DOES THE EMER DEPRESS SWITCH-LIGHT DO?

Answer 2

EMER DEPRESS
ON – Indicates switch has been selected.
Each CPC has a dedicated emergency depressurization circuit that is separate from its normal operation and won’t be affected by a failure of the CPC. When pressed the CPC drives the outflow safety valves full open and will maintain an altitude of 14,250 +/- 750 feet. If below 14,250 the aircraft will be depressurized.

Question 3

WHAT DOES THE PRESS CONT SWITCH-LIGHT DO?

Answer 3

PRESS CONT
FAULT – Indicates both CPCs have failed.
MAN – Indicates manual mode is selected.

Question 4

WHAT DOES THE MAN RATE KNOB DO?

Answer 4

MAN RATE

Controls the rate of change of the cabin altitude in manual mode.

Question 5

WHAT DOES THE CPAM DO?

Answer 5

In addition to the 2 CPCs, the aircraft also has a Cabin Pressure Acquisition Module (CPAM).
The CPAM communicates with the DCUs and provides pressurization data for display on EICAS. The EICAS indications are as follows:
Cabin Altitude (CALT)
Cabin rate of climb or decent (RATE)
Differential Pressure (P)
The CPAM is also responsible for:
CABIN ALT caution message at 8,500 feet.
CABIN ALT warning message at 10,000 and Aural “CABIN PRESSURE”.
At 10,000 feet the CPAM illuminates the PED/FASTEN SEAT BELT signs if selected auto.
At 14,000 the PASS OXY masks automatically drop.
After landing (WOW) and 3 min passes the CPAM will switch CPCs.

Question 6

WHAT WILL HAPPEN IF THE CPAM FAILS?

Answer 6

If the CPAM fails, the standby CPC will generate the EICAS messages but automatic drop down of pax masks and pax signs is lost.