Pressurization

Question 1

Where does auto mode get information on

pressurizing the cabin?

Answer 1

MCDU

origin airport, cruise altitude, and LFE

Question 2

What is the maximum cabin pressure differential?

Answer 2

7. 8 PSI up to FL370

8. 34 PSI above FL370

Question 3

Why must the cruise altitude be adjusted in
MCDU if there is a cruise altitude lower than
planned?

Answer 3

Because the computer will assume you
will continue the climb and over
pressurize the cabin.

Question 4

What does the pressurization dump button

do?

Answer 4

PACKs turn off, recirculating fans turn

off, outflow valve opens to command a 2000 fpm cabin climb to 12,400

Question 5

What if we are in the manual mode and we press the pressurization dump button?

Answer 5

PACKs and fans still turn off, but the pilot must control the cabin altitude with the
CABIN ALT selector.

Question 6

When do we use LFE CTRL?

Answer 6

When the field is not in the database to manually set landing field elevation
(EICAS indication)

Question 7

If we are cruising at FL350 and PACK 1 fails, how should we adjust our cruising altitude?

Answer 7

Descend to FL310 or below

Question 8

What are the sources of bleed air?

Answer 8

Engine (stage 6 and10) and APU

Question 9

What is the maximum overpressure differential?

Answer 9

8.77 PSI

Question 10

What is the max negative pressure differential?

Answer 10

• 0.05 PSI

Question 11

What do we use to protect the cabin from over or under pressurization?

Answer 11

Positive and negative pressure relief valves