18 Pneumatic System (Bleed Air)

Question 1

What is 14th-stage bleed air used for?

Answer 1

Cowl anti-ice
Wing anti-ice
Thrust reversers

Question 2

What is 10th-stage bleed air used for?

Answer 2

• Engine starting
• Air conditioning and pressurization

Question 3

With isolation valve closed, how is APU or external bleed air distributed?

Answer 3

With the isolation valve closed, the left manifold may be pressurized from external air, APU or left engine bleed air. The right engine bleed air normally pressurizes the right manifold.

Question 4

What is 7th-stage bleed air used for?

Answer 4

Pressurization of oil seals and the venting of engine sumps in the lubrication system.