Pressurization

Question 1

Where is the position of the outflow valve displayed?

Answer 1

ECS synoptic page of MFD

Question 2

The CPCS can operate in which modes?

Answer 2

Both manual and automatic

Question 3

Which of the following are components of the CPCS?

Answer 3

Cabin Pressure Controller (CPC),

Cabin Outflow Valve (OFV),

Positive Pressure Relief Valve (Safety Valve),
&
Negative Pressure Relief Valve (NPRV)

Question 4

The pressurization panel is found where?

Answer 4

Overhead panel

Question 5

True or False: The basic function of the CPC is to modulate the outflow valve in order to maintain proper cabin pressure.

Answer 5

True

Question 6

True or False: The CPC modulates the outflow valve based on information received from various aircraft sensors and systems.

Answer 6

True

Question 7

True or False: The CPC is a quad channel controller.

Answer 7

False

[Dual = active and standby - manual modes of these allows for pilot manual pressure control]

Question 8

True or False: If a CPC channel should fail, an EICAS message will be displayed.

Answer 8

True

Question 9

The outflow valve _______ to increase cabin pressure and _______ to decrease cabin pressure.

Answer 9

Closes, opens

Question 10

True or False: Normally, the outflow valve is modulated automatically by the CPC.

Answer 10

True

Question 11

What is the proper way to increase cabin pressure while operating in the manual mode?

Answer 11

Rotate the Cabin Altitude selector knob to the down position

Question 12

The Negative Pressure Relief Valve serves which purpose?

Answer 12

Prevents damage to the aircraft structure due to excessive negative differential pressure

Question 13

The Negative Pressure Relief Valve is operated how?

Answer 13

Spring loaded

[-check valve - opens automatically based on pressure differential]

Question 14

At which point will the Negative Pressure Relief Valve open?

Answer 14

If there is a pressure differential that exceeds -.5 psi between the cabin and the surrounding environment

Question 15

True or False: The Negative Pressure Relief Valve requires no electricity to operate.

Answer 15

True

Question 16

The Positive Pressure Relief Valve is operated how?

Answer 16

Spring loaded

[-check valve opens automatically based on pressure differential]

Question 17

True or False: The Positive Pressure Relief Valve opens when the pressure
differential exceeds 8.6 PSI.

Answer 17

True

Question 18

True or False: The Positive Pressure Relief Valve is connected to its own static port.

Answer 18

True

Question 19

True or False: The Positive Pressure Relief Valve is installed to prevent damage to the aircraft structure due to excessive positive overpressure.

Answer 19

True

Question 20

True or False: The Positive Pressure Relief Valve’s static port is not electrically heated, due to the fact that it does not protrude from the fuselage.

Answer 20

False

Question 21

At which point would the Positive Pressure Relief Valve activate?

Answer 21

When differential pressure exceeds 8.6 psi

Question 22

True or False: The Positive Pressure Relief Valve is located in the aft section of the aircraft (aft pressure dome).

Answer 22

True

Question 23

True or False: DUMP cannot be used in the automatic mode to relieve pressure if needed. This is only done through manual mode.

Answer 23

False

[2.23 Vol 2 NOTE: “The Dump Function of the outflow valve is not available in Manual Mode. However if the button is pushed in, both recirculation fan and packs are turned off.”]

Question 24

What information does the CPCS take into account when scheduling a target cabin altitude and cabin pressure variation?

Answer 24

Gross weight,
cruise altitude,
landing field elevation

Question 25

True or False: The Negative Pressure Relief Valve only works if the Positive Pressure Relief Valve is operational.

Answer 25

False

Question 26

What is the default Landing Field Elevation (LFE) value used by the CPCS if no pilot input is made with the LFE knob when FMS field elevation is not available?

Answer 26

8,000 ft

Question 27

True or False: When cruise altitude is not available from the FMS, the cabin pressure schedule is based on ambient pressure.

Answer 27

True

Question 28

True or False: The Negative Pressure Relief Valve works independently from the normal Outflow Valve.

Answer 28

True

Question 29

In regard to the CPCS, what are the special procedures for high altitude Operations?

Answer 29

There are no special procedures for high altitude operations

Question 30

How is the DUMP function activated for the CPCS?

Answer 30

By pushing in the guarded DUMP button on the pressurization panel

Question 31

What happens when the DUMP function is activated?

Answer 31

CPCS automatically: sets the packs and recirculation fans to OFF, controls the outflow valve to maintain the cabin altitude rate of climb at 2000 ft/min up to 12,400 ft, and closes the outflow valve at 12,400 ft allowing the cabin altitude to rise by natural leak

Question 32

True or False: When the CPCS is in manual mode, no pilot input is necessary to adjust cabin pressurization.

Answer 32

False

Question 33

What will occur if the cabin altitude reaches 9,700 ft.?

Answer 33

EICAS displays message CABIN ALTITUDE HI, the aural warning “CABIN” is played on the flightdeck loudspeaker

Question 34

Automatic mode for the CPCS has which of the following modes?

Answer 34

Ground, Taxi, Takeoff, Climb, Cruise, Descent, Abort

Question 35

True or False: When the CPCS is in GROUND mode, the outflow valve is in the fully open position.

Answer 35

True

Question 36

True or False: There is a pressurization ABORT mode in the event a return to field after takeoff is necessary.

Answer 36

True

Question 37

What happens when the DUMP button is activated?

Answer 37

Sets the packs and recirculation fans to OFF (even in Manual Mode), (If not in manual mode:) controls the outflow valve to maintain the cabin altitude rate of climb at 2000 ft/min up to 12,400 ft, closes the outflow valve at 12,400 ft

Question 38

The outflow valve is manually modulated by _______.

Answer 38

Manually adjusting cabin altitude with the CABIN ALT selector knob

Question 39

True or False: The Negative Pressure Relief Valve works with a static port in order for it to function properly.

Answer 39

False

Question 40

True or False: Cruise altitude entered in the MCDU has no effect on CPC pressurization calculations.

Answer 40

False