15.11

Question 1

How do you increase and decrease power needed for the required thrust output

Answer 1

Varying flow of fuel to the combustion chamber

Question 2

What is rich blowout

Answer 2

When quantity of fuel becomes excessive limiting the temperature of blades exceeded

Question 3

When does rich blowout occur

Answer 3

Not enough oxygen in air supply to support combustion

Excess fuel cools mixture to below combustion temperature

Question 4

What is the function of fuel control systems

Answer 4

Match fuel flow to power requested by flight crew

Question 5

Fuel control sections

Answer 5

Computing and metering

Question 6

What does EEC stand for

Answer 6

Electronic engine control

Question 7

How does the fadec system work

Answer 7

No hydromechanical fuel control back up system

Question 8

How does the fadec system provide information

Answer 8

Electronic sensors to give engine parameter information to the EEC

Question 9

What does the EEC do

Answer 9

Computer that controls the operation of the engine

Question 10

What is the EEC placed

Answer 10

In part of the engine nacelle that is cool

Question 11

How many channels does the EEC have

Answer 11

2 , A and B

Question 12

What memory does the EEC have

Answer 12

Volitile and non-volitile to store performance and maintenance data

Question 13

Where is the fuel metering unit located

Answer 13

Mounted on the front face of the gearbox

Question 14

What does primary fuel system do

Answer 14

Store fuel

Question 15

What does secondary fuel system do

Answer 15

Supplies fuel to the engine

Question 16

What are the 2 parts of the fuel system

Answer 16

Distribution and control

Question 17

3 tasks of fuel distribution system

Answer 17

Supply fuel from fuel system to combustion chamber

Pressurise fuel so it vapourises in the combustion chamber

Heat the fuel

Question 18

How much does the low pressure fuel pump increase pressure to

Answer 18

175psi

Question 19

How much does the high pressure pump increase fuel pressure to

Answer 19

900 psi

Question 20

What are engine driven fuel pumps divided into

Answer 20

Constant displacement

Non-constant displacement

Question 21

What is a centrifugal pump

Answer 21

Non-constant displacement pump

Question 22

What is the boost stage of the engine driven pump

Answer 22

Where the output of the centrifugal is varied

Question 23

How is the fuel pump lubricated

Answer 23

Passing fuel through it

Never turn the pump on without a fuel flow supplied to the inlet

Question 24

Where is a low pressure filter

Answer 24

Between supply tanks and engine fuel system to protect engine driven fuel pumps

Question 25

Where is the high pressure filter

Answer 25

Between fuel pump and fuel control to protect fuel control from contaminants brought by low pressure pump

Question 26

3 types of filters used

Answer 26

Micron Wafer screen Plain screen mesh

Question 27

What filter has the greatest filtering action

Answer 27

Micron Porous cellulose can remove FOD up to 10-25 microns

Question 28

What’s the most widely used filter

Answer 28

200 mesh 35 mesh micron filters Used in fuel pumps and fuel controls

Question 29

What does the wafer type filer have

Answer 29

Replaceable element made of layers of screen disks

Question 30

What are mesh filters made of

Answer 30

Mesh steel wire

Question 31

What does the heat exchanger use to heat up fuel to stop water freezing

Answer 31

Engine bleed air or engine oil

Question 32

How do we protect connections in fluid lines against leaks

Answer 32

Shrouded connections Double sealed connections

Question 33

What does a shrouded connection do

Answer 33

Doesn’t prevent a leak but catches leaks and carries them away by the engine drain system

Question 34

How many manifold does a simplex nozzle need

Answer 34

One

Question 35

How many manifolds does a duplex nozzle need

Answer 35

Dual manifold and pressuring valve or flow divider to divide primary and secondary main fuel flow

Question 36

What is external mounting

Answer 36

where a mounting pad is provided to attach nozzle to case or inlet air elbow

Question 37

What is internal mounting

Answer 37

At the liner dome the chamber cover is removed for replacement or maintenance of the nozzle

Question 38

What are primary fuel nozzles

Answer 38

Set of simple nozzles used for engine start up to idle speed

Question 39

What are secondary fuel nozzles

Answer 39

Second set of simplex nozzles used acceleration to maximum power

Question 40

What’s a duplex nozzle

Answer 40

Dual flow nozzles which combine the 2 simplex nozzles in one

Question 41

Why is a check valve used

Answer 41

Prevent carbon formation

Question 42

When does the check valve close

Answer 42

Fuel pressure in the manifold decreases after the hp fuel shut off valve is closed

Question 43

Why is it important for the check valve to close

Answer 43

So no fuel enters the combustion chamber from the manifold by gravity

Question 44

What does crosstalk logic do

Answer 44

Compares data from channels A and B