Pressurization

Question 1

How many modes exist for controlling the outflow of cabin air through the outflow valve?

Answer 1

Two automatic modes available from two digital controllers and one manual mode.

Question 2

How many safety valves exist?

Answer 2

Two. They operate independent of the automatic and manual modes of pressurization.

Question 3

Normal operation of the pressurization system is automatic when … ?

Answer 3

The destination airport is programmed into the FMS and the FMS sends the correct landing altitude to the controller.

Question 4

What is the IASC?

Answer 4

Integrated Air System Controller

Question 5

What does the IASC control? (4)

Answer 5

All automatic phases of pressurization
pneumatic
air conditioning
ice and rain protection

Question 6

How many IASC are there.

Answer 6

Two
In the auto mode, each can drive the outflow valve through the auto drive mechanism of its actuator.
In the manual mode, IASC 1 drives the outflow valve through the manual drive mechanism of its actuator.

Question 7

Are both IASC active at the same time?

Answer 7

No. One is active and the other is in standby. If one fails, the other takes over. IASC 1 typically is the active controller on power-up.

Question 8

Where are the safety valves located?

Answer 8

Aft pressure bulkhead

Question 9

Describe the Manual Rate knobs positions and rates of change …

Answer 9

12 o’clock corresponds to 0
@ 2/3 angle range left or right equates to -1000 to +1000 fpm
Full left or right obtains 2500 fpm

Question 10

EMER DEPRESS in the auto mode depressurizes …

Answer 10

2500 fpm up to 14,000’ + - 100’ or aircraft altitude, whichever is lower

Question 11

EMER DEPRESS in the manual mode depressurizes …

Answer 11

3000 fpm up to 14,500’ + - 500’ or aircraft altitude, whichever is lower

Question 12

What does the DITCHING switch do …

Answer 12

Depressurizes the cabin
Shuts off the A/C
Closes the Outflow Valve

Question 13

What altitude is the DITCHING switch inhibited?

Answer 13

Above 15,000’ and only in the Auto mode

Question 14

What other means is there to close the Outflow Valve?

Answer 14

Turn the Manual Rate knob fully down

Question 15

Cabin Altitude Amber is set at what altitude?

Answer 15

8500’

Question 16

Cabin Altitude Warning is set at what altitude?

Answer 16

9400’

Question 17

The Pressurization Mode is activated when …

Answer 17

Thrust levers advanced for takeoff. Cabin initially pressurized to 300’ below field.

Question 18

On takeoff, the aircraft will maintain 300’ below field elevation until when …

Answer 18

6000’ AGL or
10 minutes elapses
Takeoff and Return to Base Sequence

Question 19

A typical climb rate for the cabin is …

Answer 19

300-500 fpm. For light aircraft climbs, the maximum cabin climb is 635 fpm

Question 20

Cruise Mode is activated when … (2)

Answer 20

Aircraft rate of climb is less than 500 fpm for more than 10 seconds
Aircraft is climbing at any rate with aircraft altitude greater than 25,000’

Question 21

Descent Mode is calculated …

Answer 21

Remaining flight time. Time is calculated from aircraft speed received from the ADC

Question 22

Describe the Depressurization Sequence …

Answer 22

On landing or an aborted takeoff, the cabin depressurizes at 500 fpm and then the outflow valve goes to full open

Question 23

The Maximum Cabin Altitude is …

Answer 23

7850’

Question 24

When taking off or landing at a field above 7850’, the Cabin Altitude caution is set …

Answer 24

To field altitude +650’ with a maximum limit of 14,300’

Question 25

When taking off or landing at a field above 7850’, the Cabin Altitude warning is set …

Answer 25

To field altitude +1550 with a maximum limit of 14,300’

Question 26

Cabin Delta P warning

Answer 26

Greater than 9.2 or less that -0.5 psid