Pneumatics

Question 1

The pneumatic air source is:

• LP and HP air
• Ram air
• HP bleed air
• LP bleed air

Answer 1

• LP and HP air

Question 2

With an electrical failure to the bleed air system:
- All valves and controls will remain in the position they were at the time of
failure.
- The high pressure valve will remain open, the RV will function in the
pressure regulating mode.
- The high pressure valve will be closed, the PRV will be at shutoff and the
flow control valve reverts to minimum flow
- The HP bleed valve will fail safe to close, the system will supply low pressure bleed air at maximum flow regardless of BLEED AIR flow control knob position.

Answer 2

• The HP bleed valve will fail safe to close, the system will supply low pressure bleed air at maximum flow regardless of BLEED AIR flow control knob position.

Question 3

The FLOW RATE CONTROLLER functions to:

• Increase deicer bleed-air temperature.
• Control the position of both HP shutoff valves.
• Adjust the air-conditioning bleed air volume from both engines.
• Decrease the deicer bleed air temperature.

Answer 3

• Adjust the air-conditioning bleed air volume from both engines.

Question 4

The bleed air over temperature sensor functions to:

• Alert the crew (by the affected BLEED HOT light) to immediately turn off
  both BLEED switches.
• Close the HP shutoff valve when duct pressure increases to 55 psi.
• Close the nacelle shut-off valve above 290° C (550° F).
• Close the affected deicing pressure regulator at 27°C

Answer 4

• Close the nacelle shut-off valve above 290° C (550° F).