Chapter 3 Midterm

Question 1

A blank is defined as one takeoff and landing.

Answer 1

Cycle

Question 2

What three elements in order are needed to start a gas turbine engine

Answer 2

Starter, ignition, fuel

Question 3

During gas turbine engine starting the most critical parameter is?.

Answer 3

Egt

Question 4

Please indicate two variations of a bore scope.

Answer 4

** flexible and ridged **

Question 5

If the engine fails to self accelerate or does not reach idle rpm position the engine is said to have had a ?.

Answer 5

Hung start.

Question 6

Define hot start

Answer 6

Is indicated if the exhaust gas temp exceeds specified limits.

Question 7

What are two methods for permanently marking aircraft turbine parts?.

Answer 7

Laser etching, engraving

Question 8

Please list and define the different part tags and their associated color coding.

Answer 8

Red- not airworthy, green-repair, not airworthy, yellow- good/airworthy.

Question 9

What type of starter is generally used for small turbine engines

Answer 9

Starter generator

Question 10

What type of starter is generally used for large turbofan engines

Answer 10

Air turbine starter uses bleed air.

Question 11

Please define engine trim

Answer 11

A maintenance procedure in which the turbine engine fuel control is adjusted

Question 12

What is dry trim?. Wet trim?

Answer 12

Dry trim- no water. Wet trim- water injection

Question 13

What is a partial power stop

Answer 13

Trim tool used to adjust fcu

Question 14

What is meant by a remote trimmer

Answer 14

Trim tool used to remotely adjust fcu

Question 15

When is trim normally accomplished please give four examples

Answer 15

Major fuel comp, R&R, engine change/overhaul, failed power assurance check, pilot write up

Question 16

What is trend analysis and how is it used with turbine engines

Answer 16

Engine performance monitoring over a period of time looking for anything unusual.

Question 17

What is FOD

Answer 17

Demise caused by engine ingestion of foreign materials

Question 18

List the steps of the overhaul process

Answer 18

Receiving, tear down, cleaning, inspection, repair, re assembly, testing

Question 19

Common repairs made during engine overhaul process

Answer 19

Thread repairs, blending, tubing repairs

Question 20

What is a helicoil insert used for

Answer 20

Thread repair

Question 21

What is a labyrinth seal

Answer 21

Oil seal

Question 22

Three types of non destructive inspection techniques used during turbine overhaul

Answer 22

Mag particle, dye penetrant, ultrasonic, eddy current

Question 23

What is the purpose of balancing the rotating assemblies of an engine

Answer 23

Eliminate vibration

Question 24

What are three methods used to balance the rotating within the engine

Answer 24

Blade mapping, dynamic balance, static balance

Question 25

What parts of a turbine engine are balanced

Answer 25

Rotating assemblies

Question 26

What is blade mapping

Answer 26

Locate/ match blade weights and install on opposite ends of the disc

Question 27

What are stress rupture cracks and where are they commonly found

Answer 27

Hot section perpendicular to the le/te

Question 28

What is blade creep and where would you typically find this condition?

Answer 28

Permanent elongation of turbine wheels

Question 29

What are the atmospheric conditions that affect thrust output

Answer 29

Temp, density, pressure

Question 30

CDP

Answer 30

Compressor discharge pressure

Question 31

TIT

Answer 31

Turbine inlet temp

Question 32

EGT

Answer 32

Exhaust gas temp

Question 33

CIT

Answer 33

Compressor inlet temp

Question 34

EPR

Answer 34

Engine pressure ratio

Question 35

Pb

Answer 35

Burner pressure

Question 36

Pt7

Answer 36

Total pressure at station 7

Question 37

Dry motoring

Answer 37

Dry turning the engine with ignition but no fuel

Question 38

Wet motoring

Answer 38

Turning the engine with fuel but no ignition

Question 39

Define hung start

Answer 39

Engine fails to reach self acceleration

Question 40

Define hot start

Answer 40

Where the engine starts but exceeds egt limits

Question 41

Purpose of a hot section inspection

Answer 41

Check integrity of turbine, combust ears, and exhaust for cracks and distortion

Question 42

Common types of damage that occurs in the hot section

Answer 42

Cracks

Question 43

Manufacturers base engine overhauls based on operating hours or

Answer 43

Cycles

Question 44

Why is it important to not mark the hot section with a lead pencil

Answer 44

Causes cracks

Question 45

Engines are normally disassembled horizontally or?

Answer 45

Vertically

Question 46

Describe long term preservation process

Answer 46

Place silica bags, close all ducts, drain oil, add preservation oil, remove engine place in sealed container with humidity card