Fuel/Anti-Stall

Question 1

Primary Function of the Turbine Engine FUEL system:

Answer 1

provide engine with the correct amount of fuel flow for all operating conditions.

Question 2

It may also be used as servo pressure (muscle pressure) for secondary functions such as Anti-Stall Systems actuation (vbv, vsv), active clearance control operation, as well as for Oil Cooling (Engine or CSD/IDG oil).

Answer 2

HP engine fuel

Question 3

What ATA chapter if the fuel is in the WING FUEL TANK/BOOSTER PUMP?

Answer 3

ATA 28

Question 4

What ATA chapter if the fuel is in the Engine?

Answer 4

ATA 73

Question 5

It cuts off fuel supply to the engine

It is controlled by ENGINE FIRE HANDLE

Also controlled by fuel/ign switch in some aircraft

Answer 5

SOV (Spar Valve)

Question 6

____ stage pump boosts fuel flow thru fuel heater (fuel/oil heat exchanger) and can also suction fuel from wing tank.

Answer 6

1st stage pump/impeller pump

Question 7

the _____ stage delivers high press fuel to FCU.

Answer 7

2nd stage / gear pump

Question 8

Where can you find the fuel pump?

Answer 8

at the AGB attached to FCU

Question 9

3 modes of Fuel heater:

Answer 9

Hot

Cold

Bypass

Question 10

What does fuel heater uses to heat the fuel?

Answer 10

hot engine oil - to prevent ice formations entering the FCU

Question 11

Type of filter that consist of metal screen discs and withstands HP.

Answer 11

Wafer Screen

Question 12

Type of filter that is made up of wire screen and often formed into cone. Used in uncritical areas.

Answer 12

Plain mesh

Question 13

Type of filter named after the particle unit.

Answer 13

Micron filter

Question 14

Filters often have a _______ _______ switch installed to provide flight deck indication of Fuel Filter Clogging

Answer 14

differential pressure

Question 15

______ controls the flow of fuel to the required quantity necessary for engine operating conditions (starting, decel/acceleration, cruise, take-off, landing, shut-down, emergency).

Answer 15

FCU

Question 16

4 types of FCU

Answer 16

1) Hydro-Mechanical
2) Hydro- Pneumatic
3) Supervisory E.E.C.
4) Electronic (F.A.D.E.C)

Question 17

Type of FCU that uses flyweight governor, cables, pushrods etc. It meters fuel to the combustion chamber iaw power demand.

Answer 17

Hydro-Mechanical

Question 18

Type of FCU that uses 2 speed governors and is used for turboprop and turboshaft engines. Also for turbofan engines.

Uses air and fuel pressures to meter fuel

N1 governor for compressor turbines speed and N2 for power Turbine speed.

Answer 18

Hydro-Pneumatic

Question 19

adds FADEC technology to Hydro Mechanical system (HYBRID) and not common but still found

EEC (Electronic Engine Control) operates as a limiter to prevent engine paratmeters such as tem and rpm from being exceeded.

Answer 19

EEC FCU System/Electronic Hydro-Mechanical

Question 20

The “Dual Channel” FADEC EEC is the main and central component, it is installed on the Fan case. 1 channel manages the _____, other is in _____ ______.

Answer 20

engine, standby mode

Question 21

The _____ meters fuel iaw commands from the EEC, it is istalled on the AGB.

Answer 21

HMU

Question 22

EEC has a dedicated ______ that is driven by the AGB.

Answer 22

alternator

Question 23

2 Functions associated with HMU: (HMU is fully commanded by the EEC)

Answer 23

Fuel Metering

Servo Control

Question 24

The ____ (aka ECU) does all computing and commands HMU.

Answer 24

EEC

Question 25

How does fuel flow indicated?

Answer 25

weight per hr

Question 26

Type of nozzle that has 2 supply lines and 2 spray patterns at the fuel nozzle, designated Primary (inner) and Secondary (outer main) flow.

Answer 26

Duplex nozzle

Question 27

\_\_\_\_\_\_ _______ delivers fuel to the nozzles.

Answer 27

fuel manifold

Question 28

\_\_\_\_\_\_\_\_ nozzles can be either single conical spray or dual conical spray (Primary & Secondary flows), a flow divider is built into the fuel nozzle.

Answer 28

Simplex

Question 29

\_\_\_\_\_\_ _______ (Fuel Pressurizing and Dump Valves), aka flow dividers, serve 2 functions: 1. schedule (divide) primary & secondary fuel flow to the duplex fuel nozzles 2. provide positive fuel cutoff at engine shutdown by draining fuel from the fuel supply manifold(s

Answer 29

P&D valves

Question 30

What is the purpose of draining fuel at Engine Shutdown?

Answer 30

**Reduce** the risk of a tailpipe fire due to residual fuel burning after engine is shut down (or next engine start) **Preven**t carbon buildup in the fuel nozzles

Question 31

2 types of drain valves:

Answer 31

Fuel Manifold Dump valve - located at the low points of fuel manifold Combustor Drain Valve - runs thru a P&D valve and recovered for next engine start

Question 32

gas turbine fuel:

Answer 32

Question 33

Compressor Anti-Stall systems:

Answer 33

Variable Bleed Valves Bleed bands Variable inlet guide vanes Variable stator vanes Transient bleed valves

Question 34

Anti-stall system located outside case of the compressor. It opens and closes ports in the compressor case spilling INTERSTAGE COMPRESSOR AIR.

Answer 34

Variable bleed valves

Question 35

What is the position of VBV?

Answer 35

Closed

Question 36

Figure of an open VBV.

Answer 36

Question 37

What will happen if primary orifice on the VBV is blocked?

Answer 37

bleed valve will stay open longer

Question 38

It is similar to the bleed valve except that with this system, air is bled from the rear stages of the compressor through the use of a band around the compressor, rather than a single valve.

Answer 38

Variable bleed bands

Question 39

Type of bleed valves that are frequently used on Large turbofan engines and operated by FADEC and EEC. They are located on the last stage of the high pressure compressor and vent excess high pressure air back into the engine at the **first stage turbine vanes.**

Answer 39

Transient bleed valves

Question 40

A mechanical action that changes the airflow coming into the compressor \_\_\_\_\_\_, or the airflow within the compressor \_\_\_\_\_\_.

Answer 40

VIGV, VSV