Pressurization

Question 1

When does the cruise phase of the pressurization system start?

Answer 1

When the aircraft is within .25 psi of the altitude set in the FLT ALT window.

Question 2

What are the indications of a single auto controller failure?

Answer 2

1. AUTO FAIL light illuminated.
2. ALTN light illuminated.

Question 3

What warnings will occur if the cabin altitude exceeds 10,000 feet?

Answer 3

The cabin altitude warning horn sounds.

Question 4

Which relief valve prevents ambient pressure from exceeding cabin pressure by an excessive amount?

Answer 4

Negative pressure relief valve.

Question 5

How many DC motors are able to control the outflow valve?

Answer 5

The pressurization system utilizes 3. Two auto and one manual.

Question 6

What warnings will occur if the cabin altitude exceeds 10,000 feet?

Answer 6

The cabin altitude warning horn sounds.

Question 7

Cabin Pressurization: AUTO FAIL light amber.

Answer 7

Automatic pressurization system failure detected.

• indicates single controller failure when ALTN light illuminated

Indicates dual controller failure when illuminated alone

Question 8

Pressurization system: OFF SCHED DESCENT LIGHT.

Answer 8

Aircraft descended before reaching cruise altitude set in the FLT ALT Indicator

Question 9

Pressurization system: ALTN light illuminated.

Answer 9

Pressurization system operating in the alternate automatic mode:

• with auto fail illuminated, single controller failure
• pressurization mode selector in ALTN mode

Question 10

How many cabin pressure controllers are there?

Answer 10

There are two

Question 11

Does each cabin pressure controller have a motor?

Answer 11

Yes, each cabin pressure controller has a DC powered motor.

Question 12

What conditions will illuminate the amber AUTO FAIL light?

Answer 12

• Controller fault
• Outflow valve control fault
• Excessive differential pressure
• Excessive rate of cabin pressure change
• Loss of DC power
• High cabin altitude

Question 13

Where does the Cabin Pressure controllers receive information from?

Answer 13

• ADIRU (air data inertial reference units)
• SMYD (stall management and yaw damper computers)
• Air/ground logic from PSEU (proximity switch electronics unit)
• Actual cabin pressure
• Left and Right pack valve position
• overboard exhaust valve position

Question 14

Which switch is used to control cabin pressure when in the manual mode of the system?

Answer 14

A spring loaded outflow valve switch.
This will cause a green MANUAL light to illuminate