Cabin Pressure Control System (CPCS)

Question 0

How many channels does the CPC have

Answer 0

2, they are alternated after each flight

Question 1

What components make up the CPCS

Answer 1

• Cabin pressure controller (CPC)
• 1 cabin outflow valve (OFV)
• 1 negative pressure relief valve (NPRV)
• 1 positive pressure relief valve (safety valve)
• static pressure port

Question 2

When does the neg pressure relief valve open

Answer 2

When the pressure difference between the cabin and surrounding environment exceeds -.5 psi

Question 3

When does the positive pressure relief valve open

Answer 3

When the difference in pressure between the cabin and surrounding environment exceeds 8.6 psi

Question 4

Which data does the CPCS use to determine the target cabin alt and cabin press variation rate

Answer 4

• Landing field elevation
• cruise altitude
• gross weight

Question 5

Explain the differential pressure schedule

Answer 5

If the FMS cruise flight level is set below 37,000 ft? The diff pressure of 7.8 is used.

If either the cruise level is set higher than 37,000 ft or the airplane is actually flying above 370, the diff pressure switches to 8.4

Question 6

What does the CPCS do when the DUMP button is pressed

Answer 6

• Sets the ECS packs and recirculation fans to OFF
• controls the outflow valve to maintain the cabin alt rate if climb at 2,000 fpm up to 12,400 ft
• at cabin alt of 12,400 ft, the outflow valve is fully closed.

Question 7

At what altitude do you get a CABIN ALT HI warning message

Answer 7

Cabin alt is 9700 ft or higher. Or +500 ft above LFE for LFE higher than 9400 ft