Chapter 6.20 - Pressurization Systems

Question 1

When is the overboard exhaust valve normally closed?

Open?

What non-normal condition will open the overboard exhaust valve?

Answer 1

• In flight with high differential pressure
• On the ground, and
• In flight with low differential pressure
• 700
• Opens if either pack switch is in HIGH, and
• The recirculation fan is OFF
• 800/-900
• Opens if either pack switch is in HIGH, and
• The right recirculation fan is OFF

Question 2

What causes the amber AUTO FAIL light?

Answer 2

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

Question 3

How can you determine if a pressurization system failure is a single or dual controller failure?

Answer 3

Single failure - AUTO FAIL and ALTN lights illuminate

Dual failure - only AUTO FAIL light illuminates

Question 4

What causes an amber OFF SCHED DESCENT light?

Answer 4

Aircraft descended before reaching the altitude set in the FLT ALT indicator

Question 5

How can the OFF SCHED DESCENT light be extinguished?

Answer 5

Change the FLT ALT window to aircraft altitude

Question 6

What LAND ALT elevation will be used if the aircraft descends prior to reaching the altitude in the FLT ALT indicator?

Answer 6

Takeoff field elevation

Question 7

When will the cabin altitude warning horn sound?

What else uses this horn?

Answer 7

10,000 feet

This is the same as the takeoff warning horn

Question 8

What occurs when the HIGH ALT LDG switch is selected on?

Answer 8

Reprograms cabin altitude warning annunciation from 10,000 feet to 12,650 feet