A320 Pneumatics Questions

Each bleed valve is electrically operated and controlled pneumatically by its associated BMC.

• True.
• False.

Explanation: False - it's the reverse: each bleed valve is pneumatically operated and controlled electrically by its associated BMC.

Pneumatic - Description, Engine Bleed System (General)

The crossbleed valve has two electric motors; one for the automatic mode and one for the manual mode:

• True
• False

Explanation: True - the crossbleed valve is driven by two electric motors, one dedicated to automatic mode and one to manual mode.

Pneumatic - Description, Crossbleed (General)

A check valve near the crossbleed duct protects the APU when bleed air comes from another source:

• True.
• False.

Explanation: True - a check valve near the crossbleed duct protects the APU when bleed air is being supplied from another source.

Pneumatic - Description, APU Bleed Air Supply (General)

The pressure regulating and shutoff valve will close if _______ pressure is _______ or _______ airflow occurs

• Downstream / low / reverse
• Downstream / High / reverse
• Upstream / low / reverse

Explanation: The pressure regulating and shutoff (bleed) valve closes pneumatically if upstream pressure drops too low, or if there's reverse (return) airflow.

Pneumatic - Description, Engine Bleed System (Pressure Regulation and Limitation)

The maximum cabin descent rate is limited in automatic to:

• 300 ft/min.
• 750 ft/min.
• 1000 ft/min.
• 550 ft/min

Explanation: The maximum cabin descent rate is limited to 750 ft/min in automatic mode.

Limitations - Air Bleed/Cond/Press/Vent

Air bleed from the engines is:

• Not cooled prior to being used by the systems.
• Cooled in a heat exchanger by cooling air bleed from Fan section.
• Cooled using ambient air.
• Only cooled in air conditioning part.

Explanation: Engine bleed air is cooled in a precooler - an air-to-air heat exchanger that uses cooling air bled from the engine's fan section.

Pneumatic - Description, Engine Bleed System (Temperature Regulation and Limitation)

Engine bleed air temperature is controlled by:

• Engine oil.
• A pre-cooler that uses fan air.
• Conditioned air from the mixing unit.

Explanation: Engine bleed air temperature is controlled by a precooler that uses fan air as the cooling source.

Pneumatic - Description, Engine Bleed System (Temperature Regulation and Limitation)

Which source controls the crossbleed valve?

• Pneumatic.
• Electric.

Explanation: The crossbleed valve is controlled electrically, via a rotary selector on the AIR COND panel.

Pneumatic - Description, Crossbleed (General)