Jack's Questions

Question 1

How are nozzle guide vanes cooled?

Answer 1

Compressor discharge air

Question 2

What is compressor stall?

Answer 2

A compressor stall causes the air to stop

(if it reverses, it’s known as a surge)

Compressor stall occurs as a result of the inbalance of the vector quantities Compressor RPM + Air inlet velocity

Question 3

List the primary engine indications

Answer 3

• Engine Vibration
• Engine Pressure Ratio (EPR)
• Engine Rotational speeds (N1, N2 , N3)
• Exhaust Gas Temperature (EGT)
• Fuel flow
• Engine Torque

Question 4

What are the main parts of the cold section?

Answer 4

Inlet

Compressor

Question 5

Name two types of starter motor

Answer 5

Pneumatic ( Engines)

Electric (APU + turboprop)

Question 6

State the advantage of a starter/genny

Answer 6

• Weight saving as two components in one

some APUs + corporate jets

Question 7

What is the air pressure for a pneumatic starter?

Answer 7

The power source is low-pressure air of between 30 and 45 psig supplied from either the on-board APU or from a ground pneumatic supply cart.

Question 8

State the advantage of a pneumatic starter

Answer 8

High power to weight ratio

• it weighs approx. 20% of the weight of a comparable electric starter