Pneumatics

Question 1

What are the 3 operational modes of the pneumatic system?

Answer 1

1. Pressure Regulated Mode (Dual Pack Mode)
   
   • 18 to 40 psi: 7th stage air; below 18 psi: 12th stage air
2. Pressure Regulated Mode (Single Pack Mode)
   
   • 30 to 40 psi: 7th stage air; below 30 psi: 12th stage air
3. Temperature regulated mode – Cowl or Wing Anti Ice selected ON: 12th stage air

Question 2

What is the limitation for flight with a bleed air switch selected OFF?

Answer 2

Descend to 41,000 feet or below

Question 3

What is the purpose of the isolation valve?

Answer 3

• Eliminates problems of two engine flow sharing and

- Allows availability of all pneumatic systems with one bleed air turned off

Question 4

What actions would cause the isolation valve to open?

Answer 4

• Selecting the isolation valve switch ON
• Selecting the APU air switch ON
• Selecting either the master start or crank switch to ON

Question 5

What is indicated by a red “PYLON HOT” CAS message and what is the initial corrective action?

Answer 5

• Pylon temperature > 325°F

- Turn the appropriate bleed air switch to “OFF”

Question 6

What is indicated by an amber “BLEED PRESS HI” CAS message and what is the initial corrective action?

Answer 6

• Bleed air pressure in the manifold > 75 psi

- Turn the appropriate bleed air switch to “OFF”

Question 7

What is indicated by an amber “BLEED AIR HOT” CAS message and what is the initial corrective action?

Answer 7

• Bleed air temperature in the manifold > 550º F

- Turn the appropriate bleed air switch to “OFF”