Turbine Operation + Maintenance

Question 1

Tachometer is measured in ______.

Answer 1

Percent of RPM

Question 2

The difference between two separate pressure measures in a turbine engine:

Answer 2

Engine pressure ratio

EPR

Question 3

EPR is the ratio of _____ to the ______.

Answer 3

Turbine discharge pressure,

Compressor inlet pressure.

Question 4

2 types of jet engines measured in torque:

Answer 4

Turboshaft.

Turboprop.

Question 5

EGT reading after the normal redline:

Answer 5

Transient “Redline”

Question 6

The two levers on a dual lever turboprop are _____ and _____.

Answer 6

Power lever.

Fuel/Condition lever.

Question 7

The most catastrophic starting issue:

Answer 7

Hot Start.

Question 8

May occurr if fuel is introduced too early in starting process

Answer 8

Hot start.

Question 9

May occurr if starter cuts out too early:

Answer 9

Hung start.

Question 10

Three types of turbine engine throttles systems:

Answer 10

1) Full Throttle
2) Flat Rated / Part Throttle
3) De-rated

Question 11

Explain what is meant by a “full throttle” turbine engine.

Answer 11

On a standard day, the full forward position produces the rated HP.

Question 12

Explain what is meant by a “flat rated” (aka part throttle) turbine engine.

Answer 12

Designed for a certain amount of thrust. Advance levers to achieve the desired engine measurements.

Question 13

Explain what is meant by a “de-rated” turbine engine:

Answer 13

Capable of more HP than needed. Power lever is blocked to prevent overworking engine.

Question 14

Method of turbine engine construction in which the engine is made up of several units that can be removed independent of the rest of the engine:

Answer 14

Modular engine construction.

Question 15

The 4 steps in the “OPERATING CYCLE” of a turbine engine:

Answer 15

1) Starting the engine.
2) Taking off.
3) Landing.
4) Shutting the engine down.

Question 16

A system of routine comparison of engine performance with a base line of the same parameters when the engine was new:

Answer 16

Trend Monitoring.

Question 17

Maintenance program that monitors operating condition of engine and allows repairs to be made when performance deteriorates rather than on a predetermined time schedule:

Answer 17

On-condition maintenance

Question 18

2 types of maintenance programs:

Answer 18

1) On-condition maintenance.

2) Trend Monitoring.

Question 19

A tool used for viewing the inside of a turbine engine without having to disassemble it:

Answer 19

Borescope

Question 20

On a single-shaft turboprop engine, the _______ lever affects the prop angle when on the ground.

Answer 20

Power lever.

Question 21

T/F

On a free-turbine turboprop engine, the power lever increases/decreases airflow.

Answer 21

False.

Fuel flow.

Question 22

When should a hot section inspection be performed?

Answer 22

On a time/cycle basis or anytime the EGT becomes excessive.

Question 23

T/F

Felt tipped markers are approved for marking parts when disassembling the hot section of the engine.

Answer 23

True.

No lead, wax, or grease pencils allowed

Question 24

4 basic rules for systematic troubleshooting:

Answer 24

1) Know the way the system should operate.
2) Observe how the system is operating.
3) Divide the system to find the trouble.
4) Look for obvious problem first.

Question 25

A method of repairing damaged compressor and turbine blades with a file:

Answer 25

Blending

Question 26

The high velocity stream of turbulent air behind an operating aircraft engine is called the _______.

Answer 26

Wake

Question 27

No one should approach within ________ of an inlet duct when engine is operating.

Answer 27

25 feet.

Question 28

The hazard area extends around _____ feet behind an idling turbojet and _____ feet behind it when the engine is developing takeoff thrust.

Answer 28

100. | 200.

Question 29

3 instruments to monitor when starting a turbine engine:

Answer 29

1) EGT indicator. 2) Tachometer. 3) Oil pressure gauge.

Question 30

2 criteria used to determine when a turbine engine overhaul is needed:

Answer 30

1) Operating hours. | 2) Operating cycles.

Question 31

________ normally cause high EGT and unsatisfactory acceleration.

Answer 31

Dirty compressor blades.

Question 32

T/F | When blending a compressor or turbine blade, always file perpendicular to the blade edge.

Answer 32

False. | Parallel to the blade edge.

Question 33

2 types of liquid washing:

Answer 33

1) Desalination washing. | 2) Performance-recovery washing.

Question 34

2 ways to clean compressors:

Answer 34

1) Grit blasting. | 2) Liquid washing.

Question 35

5 parts of the hot section:

Answer 35

1) Fuel nozzles. 2) Combustion chambers. 3) Turbine inlet guide vanes. 4) Turbine wheels + blades. 5) Exhaust system.

Question 36

Unless otherwise stated in the service manual, specified torque values are for _____, _____ threads.

Answer 36

Clean, | Dry.

Question 37

3 components of the cold section of a turbofan engine:

Answer 37

1) Inlet Fan. 2) Compressor. 3) Diffuser.

Question 38

The JetCal Analyzer has these three master instruments:

Answer 38

1) EGT. 2) Tachometer. 3) EPR.

Question 39

N1 =

Answer 39

Rotational speed of low-pressure compressor.

Question 40

The speed attained by a gas turbine engine during startup that allows it to continue with no further assistance:

Answer 40

Self accelerating speed

Question 41

A test run to determine the way an engine’s performance compares with its performance when it was new:

Answer 41

Power-assurance check

Question 42

4 sources of data used by the engine manufacturer for purposes of trend monitoring:

Answer 42

1) Fuel flow 2) EGT 3) N1 4) N2

Question 43

3 basic routine inspections:

Answer 43

1) Pre-flight inspection 2) Cold-section inspection 3) Hot-section inspection

Question 44

Rotating a turbine engine with the starter while the fuel and ignition are turned off is called:

Answer 44

Motoring the engine

Question 45

When starting a turbine engine, engage the starter first for what reason?

Answer 45

To clear out any remaining fuel vapor from the combustion chamber.

Question 46

Dirty compressor blades normally cause:

Answer 46

1) High EGT | 2) Unsatisfactory acceleration

Question 47

T/F | Bent compressor blades can be straightened by the mechanic.

Answer 47

False. | Should be sent out for major repair

Question 48

T/F | Hot section inspections can usually be performed with the engine on the airframe.

Answer 48

True

Question 49

2 critical measurments taken during hot section inspection:

Answer 49

1) Clearance between tips of the turbine blades and the housing. 2) Clearance between the turbine wheel and the exhaust cone.

Question 50

Waviness of the leading edge of a turbine blade indicates ______.

Answer 50

Overheating

Question 51

______ is cause for an inspection of the fan and compressors.

Answer 51

Overspeed

Question 52

_________ is cause for inspection of the hot section.

Answer 52

Over-temperature

Question 53

A portable testing instrument that connects to the aircraft instrument system:

Answer 53

JetCal analyzer

Question 54

The adjustment of the fuel control to produce the required EGT or EPR at a specified RPM:

Answer 54

Engine trimming

Question 55

On a single-shaft turboprop engine, the _______ lever affects the prop pitch while in flight.

Answer 55

Condition.

Question 56

A maintenance program that tests the engine oil for the presence of metal particles.

Answer 56

Spectrometric Oil Analysis Program. | SOAP

Question 57

The gas generator part of a turbofan, turboprop, or turboprop engine:

Answer 57

Core engine

Question 58

3 instrument readings that indicate a proper light up:

Answer 58

1) EGT stabilized at correct temp. 2) Oil Pressure indication. 3) Stabilized fuel flow.