Revision

Question 1

3 advantages of modular engine design to the operator?

Answer 1

Considered a minor repair
Easy transportation
Reduced need for spare parts
Modules replaceable on the wing
No re-balancing
Easy removal of modules

Question 2

When a fan thrust reverser system is designed what must be ensured about the airstream?

Answer 2

The cascades direct the air away from other engines and the undercarriage

Question 3

What effect will increasing the airflow velocity have on the angle of attack of a blade?

Answer 3

Decreasing angle of attack

Question 4

At what angle is the air deflected forward on a cold stream thrust reverser?

Answer 4

Between 45 and 60 degrees

Question 5

what is the optimal fuel/air mix?

Answer 5

1:15

Question 6

What is the purpose of the turbine?

Answer 6

To provide the torque to drive the compressor also driving the accessory gearbox.

Question 7

What effect will ram air have on engine thrust?

Answer 7

Engine thrust will increase

Question 8

What shape does an inlet form?

Answer 8

A divergent duct

Question 9

What percentage of air from the compressor is used for cooling?

Answer 9

70-80%

Question 10

What is meant by the term “sub critical”?

Answer 10

The demand from the engine has dropped and the shock wave has been expelled to create a bow wave causing a reduction in pressure

Question 11

Where are abradable shrouds found on a fan module?

Answer 11

On the inner wall of the fan case

Question 12

What is used in airflow linings to reduce noise and how is itachieved?

Answer 12

Honeycomb acoustic liners that convert noise energy (sound waves) into heat energy.

Question 13

What is the maximum number of stages used on a centrifugal compressor engine?

Answer 13

Two

Question 14

Why is the flame tube only secured at one end?

Answer 14

To allow for thermal expansion

Question 15

What will hotspots on the flame tube indicate?

Answer 15

The cooling airflow us not correct or the ceramic lining is damaged

Question 16

What is the most common method of attaching turbine rotor blades?

Answer 16

Fir tree root

Question 17

What components comprise the combustion section?

Answer 17

The casing and the flame tube

Question 18

What percentage of air from the compressor is used for combustion?

Answer 18

20-30%

Question 19

What are the three different methods of securing rotor blades?

Answer 19

Axial dovetail slots, circumferential dovetail slots and bolts/spins

Question 20

On engine shut down what is the contraction sequence of the turbine and the casing?

Answer 20

Turbine shrinks faster first then casing shrinks faster after

Question 21

What is the highest heat to metal contact in the engine?

Answer 21

1st stage hp turbine ngv

Question 22

How is vibration reduced in LP turbine blade?

Answer 22

By the use of shrouds

Question 23

What is the purpose of the exhaust cone?

Answer 23

The cone guides the discharge flow and prevents turbulence, it also prevents gas re-ingestion at the turbine frame.

Question 24

What section of the FCU is responsible for engine speed control?

Answer 24

The governing section (part of the computing section)

Question 25

What is the purpose of the reverse interlock?

Answer 25

To prevent power being increased until the thrust reverser is fully deployed

Question 26

Where on a FADEC engine would you normally find the FCU?

Answer 26

There is no FCU fitted to a FADEC engine

Question 27

Why must the engine be run at idle rpm prior to shutdown?

Answer 27

It allows the engine to cool down

Question 28

Which of the following pumps has the greater pumping capacity? Pressure or scavenge?

Answer 28

Scavenge

Question 29

The engine fuel system is split into which two sub systems?

Answer 29

Control and distribution

Question 30

What two methods are available for latching hydraulically operated thrust reverser do in position?

Answer 30

A latch mechanism or locks with an actuator

Question 31

What is the purpose of the de-oiler in a vent system?

Answer 31

To separate the oil from the air before the air is vented overboard

Question 32

What type of anti-freeze will damage titanium blades?

Answer 32

Methanol

Question 33

At what pressure will the frangible disc in a fire bottle burst?

Answer 33

1700psi

Question 34

Where do fire extinguisher firing circuits get their power?

Answer 34

Hot bus

Question 35

Which compressor is protected by the variable bleed valve?

Answer 35

LP compressor

Question 36

What is used for active clearance control on a compressor and why?

Answer 36

Warm air is used as there is no source of air cold enough for cooling

Question 37

If bypass fuel is used to cool the IDG, what else is usually fitted and why?

Answer 37

A recirculation valve is fitted

Question 38

What systems are affected when the fire button is pressed?

Answer 38

Fuel, hydraulic, air & electric

Question 39

What is the definition of a turbo shaft?

Answer 39

A gas turbine engine that delivers power to anything other then a prop

Question 40

What is a bowed rotor condition?

Answer 40

Where the engine bends due to different contracting and expanding rates due to temperature

Question 41

How does a centrifugal particle separator remove debris?

Answer 41

A swirl is intruded into the air flow by vanes, this cause any debris to be flung outwards

Question 42

Why do we have apu on aircraft?

Answer 42

Standby source of bleed air and electrical power in the event of engine failure.

Question 43

How is the flame tube protected from extreme temperatures of combustion?

Answer 43

By using the secondary airflow

Question 44

What is a compressor stall?

Answer 44

Airflow separation from the compressor aerofoils causing turbulent flow across the stage, the engine rpm drops and the engine can run roughly

Question 45

What effect will pneumatic engine anti-icing have on the operation of an engine?

Answer 45

EGT will rise as air is bled away from the engine