15.12

Question 1

When and engine shuts down components can bend due to expansion, what is this known as?

Answer 1

Bowed rotor

Question 2

Bowed rotors can lead to wear so manufactures recommend what?

Answer 2

Minimum waiting time between engine shutdown and engine start

Question 3

What 3 subsystems can engine air systems be divided into?

Answer 3

Compressor control, clearance control, engine cooling

Question 4

What are the compressor control subsystems controlled by?

Answer 4

Hydro mechanical fuel control unit or by FADEC

Question 5

What’s the main task of the compressor control system?

Answer 5

Prevent stall or surge

Question 6

What controls the incoming air into the HP compressor?

Answer 6

Variable stator vanes

Question 7

What are clearance control systems used for?

Answer 7

Optimise tip clearance in turbine and compressor

Question 8

What does the clearance control system match?

Answer 8

Expansion of stator case with engine case expansion

Question 9

Passive clearance control systems use?

Answer 9

Cooling air that can’t be switched off

Question 10

Compressor clearance control systems use?

Answer 10

Warm air to heat the rotor

Question 11

Cool airflow is used for?

Answer 11

Cooling and internal sealing

Question 12

Can internal air be used for sealing?

Answer 12

Yes

Question 13

External cooling can prevent what forming in the engine compartments?

Answer 13

Flammable gases

Question 14

What air intakes pick up RAM air when the aircraft moves?

Answer 14

NACA intakes