Pressurization

Question 1

Pressurization controlled by?

Answer 1

Cabin pressurization control system (CPCS)

• CPC
• Outflow valve (OFV)
• Negative pressure relief valve (NPRV)
• Positive pressure relief valve (safety valve)
• Static port

Question 2

CPC controls?

Answer 2

• Controls OFV
• 2 channels
• Alternate each flight

Question 3

OFV controls?

Answer 3

• Regulates amount of air leaving pressure vessel in order to maintain aircraft pressurization
• AUTO function controlled by CPC
• MAN function pilot request desired position of OFV
• LFE allows manual input of landing field elevation while still operating in the AUTO mode

Question 4

Negative pressure relief valve does?

Answer 4

Opens automatically when outside pressure > cabin pressure

- Limitation -0.5psi

Question 5

Positive pressure relief valve does?

Answer 5

• Opens when cabin pressure reaches 8.6 psi

Question 6

Static port does?

Answer 6

• Senses and transmits environment state pressure to the positive pressure relief valve

Question 7

Dump function does?

Answer 7

• Only works in AUTO mode
• Shut OFF packs and recirculation fans
• Allows cabin to climb to a max altitude of 12,400 feet @ 2000 feet per min climb rate