Pneumatics

Question 1

The bleed air system receives air from what three main sources?

Answer 1

• Engines
• APU
• Ground pneumatic sources

Question 2

What components and systems use bleed air?

Answer 2

• Air driven hydraulic pumps
• Wing and engine anti-ice
• Cargo heating
• Engine and APU starting
• Air conditioning and pressurization
• Potable water pressurization
• Hydraulic reservoir pressurization
• Trim air
• TAT probe ventilation

Question 3

What are the two sections engine bleed air is supplied from?

Answer 3

• Low stage
• High stage

Question 4

When does the aircraft use low stage air?

Answer 4

Primarily during high thrust settings, such as takeoff, climb, cruise

Question 5

When does the aircraft use high stage air?

Answer 5

During descents to supplement low stage air during low thrust settings

Question 6

What controls the engine bleed air system?

Answer 6

Air Supply and Cabin Pressure Controller (ASCPC)

Question 7

What valve is controlled by ASCPC?

Answer 7

High pressure valve

Question 8

What is the purpose of the ASCPC?

Answer 8

• Modulates the Pressure Regulating and Shutoff Valve (PRSOV) to limit bleed air temperature in the ducts
• controls the position of the bleed isolation valves

Question 9

When does the APU bleed air valve close?

Answer 9

Automatically when an engine is supplying bleed air