corrosion

Question 1

generate power by converting chemical energy from a hydrocrabon fuel into heat energy

Answer 1

reciprocating and turbine engines

Question 2

because of the inefficiency of the engine, much of this _____ along with ________ passes out of the engine through the exhaust.

Answer 2

heat, energy-rich gases

Question 3

the gases contain all of the constituents for a potent _____ and because of their elevated ______ corrosion forms extremely rapidly

Answer 3

electrolyte, temperature

Question 4

some of the exhaust trail areas where deposits may be trapped and not reached by normal cleaning methods

Answer 4

gaps, seams, hinges, and fairings

Question 5

exhaust deposit buildup where will be considerably slower and sometimes completely absent from certain aircraft models

Answer 5

upper and lower wing, aft fuselage, and in the horizontal tail surfaces

Question 6

store electrical energy by converting it into chemical energy and are therefore active chemical plants, complete with environment-polluting exhausts

Answer 6

batteries

Question 7

airplanes with this (1) must have their boxes protected by a material that resists corrosion from the (2)

Answer 7

lead-acid batteries, sulfuric acid fumes

Question 8

airplanes with (1) must have their battery areas protected with (2)

Answer 8

lead-aced batteries, alkaline-resistant finish

Question 9

what does the finishes have

Answer 9

bitumastic (tar) base, a rubber base, or can be polyurethane finishes

Question 10

what are highly corrosive to aluminum surfaces

Answer 10

organic materials such as food and human waste

Question 11

food service areas can be troublesome if there is a possibility of _____ getting into cracks under or behind the galley where it cannot be removed.

Answer 11

food debris

Question 12

while food is not corrosive it can ______ which can cause the structure to corrode

Answer 12

hold water

Question 13

no area of an airplane is subjected to as much hard service as the

Answer 13

wheel well area

Question 14

debris from the runway surface is thrown up into this area

Answer 14

takeoff and landing

Question 15

this can be troublesome in the winter when this is used on runways for ice control

Answer 15

chemicals

Question 16

what can remove protective lubricant and coatings

Answer 16

abrasion

Question 17

what can freeze and cause damage

Answer 17

water and mud

Question 18

one of the first places corrosion appears on the surface of an aircraft is

Answer 18

along seams and lap joints

Question 19

what kind of corrosion frequently appears on external skin areas

Answer 19

concentration cell corrosion

Question 20

entrapped in the lap joints

Answer 20

water or cleaning solvents

Question 21

water or cleaning solvents provides an effective

Answer 21

electrolyte

Question 22

what is a common trouble spot where natural sump or collection point for waste hydraulic fluids, water, dirt, loose fasteners, drill chips, and other odds and ends of debris

Answer 22

bilge areas

Question 23

quite often masks small quantities of water which settle to the bottom and set up a hidden potential corrosion cell

Answer 23

residual oil

Question 24

keeping bilge areas free of what will ensure the best protection against corrosion

Answer 24

extraneous material, including water and oil

Question 25

fasteners and areas around these fasteners are trouble spots

Answer 25

steel, titanium, cres, and nickel alloy fasteners

Question 26

fasteners are subject to high operational what

Answer 26

loads, moisture intrusion, and dissimilar metal skin corrosion

Question 27

corrosion of this type of construction (1) is chiefly the result of the entrance and entrapment of what (2)

Answer 27

spotwelded skins, moisture or other corrosive agents between layers of the metal

Question 28

particularly corrosion prone

Answer 28

spotwelded assemblies

Question 29

corrosive attack in spotwelded skins cause what

Answer 29

skin buckling or spotweld bulging, and eventually spotweld fracture

Question 30

prime spots for corrosion due to dissimilar metal contact between the steel pin and aluminum hinge tangs

Answer 30

piano-type hinges

Question 31

piano-type hinges are natural traps for

Answer 31

dirt, salt, and moisture

Question 32

piano-type hinges is used on what

Answer 32

access doors or plates

Question 33

when do piano-type hinges corrode and freeze

Answer 33

closed position between inspections

Question 34

(1) corrosion from this area will result from the entrapment of (2)

Answer 34

water entrapment areas, moisture

Question 35

design specification usually requires that the aircraft will have what that can collect moisture and fluids

Answer 35

drains

Question 36

constant abrasion by what removes the protective surfaces from engine frontal areas and cooling air vents

Answer 36

airborne dirt and dust, bits of gravel from runways and rain

Question 37

radiator coolers, reciprocating engine cylinder fins due to the heat dissipation may not be what

Answer 37

painted

Question 38

prime sources of corrosive attack with moist and salt or industrial pollutant-laden air constantly flowing over the surfaces

Answer 38

engine frontal areas and cooling air vents

Question 39

may present a corrosion problem whether carbon steel or stainless steel is used

Answer 39

control cabled

Question 40

presence of this in the preservative coating is one of the main contributing factors in cable corrosion

Answer 40

bare spots

Question 41

how is cable condition determined

Answer 41

cleaning the cable assembly, inspection for corrosion, and application of an approved preservative

Question 42

what is required when aluminum torch welding to exclude oxygen

Answer 42

flux

Question 43

flux in welded areas may contain what that are extremely corrosive to aluminum

Answer 43

lithium chloride, potassium chloride, potassium bisulphide, or potassium flouride

Question 44

use of what in electronic wiring and printed circuit boards makes them a target for corrosion

Answer 44

copper, lead, tin, and other materials

Question 45

how are circuit boards protected

Answer 45

sealing the wiring and circuit boards with a transparent film which excludes oxygen and moisture

Question 46

meaning of NDT

Answer 46

Non-destructive testing

Question 47

NDI

Answer 47

Non-destructive inspection

Question 48

NDE

Answer 48

Non-destructive evaluation or examination

Question 49

refers to any means of determining the strength and integrity of an object without destroying the object

Answer 49

non-destructive desting

Question 50

process of using the eye, either alone or with the help of various aids, as the sensing mechanism to determine the condition of a unit under inspection

Answer 50

Visual inspection

Question 51

standalone inspection but it is always an integral part of any NDI procedure

Answer 51

visual inspection

Question 52

oldest and most common form of NDI for an aircraft

Answer 52

visual inspection

Question 53

how many percent of NDI procedures are accomplished by direct visual methods

Answer 53

80

Question 54

how is visual inspection greatly enhanced

Answer 54

use of appropriate combinations of magnifyin instruments, borescopes, light sources, video scanners, and other devices.

Question 55

used to reveal surface-breaking cracks in solid, nonporous materials.

Answer 55

liquid penetrant inspection

Question 56

most aviation applications involve the use of what in a bulk process in liquid penetrant inspections

Answer 56

fluorescent penetrants

Question 57

involves high-frequency sound waves from a transmitting transducer (single or multiple elements) being transmitted into or onto the surface of a part to interrogate the material.

Answer 57

ultrasonic inspection

Question 58

what does a typical ultrasonic testing unit consists of

Answer 58

pulser/receiver, ultrasonic transducer and a display device

Question 59

is an electronic device capable of generating high-voltage electrical pulses

Answer 59

pulser/receiver

Question 60

The voltage from the pulser powers the transducer to create what

Answer 60

high-frequency ultrasonic wave energy.

Question 61

two basic ultrasonic inspection techniques

Answer 61

pulse-echo inspection and through transmission inspection

Question 62

This process uses a transducer to both transmit and receive the ultrasonic pulse

Answer 62

Pulse-Echo Inspection.

Question 63

The pulse-echo ultrasonic response pattern is analyzed on the basis of

Answer 63

signal amplitude and separation.

Question 64

This inspection employs two transducers, one to generate and a second to receive the ultrasound

Answer 64

Through-Transmission Inspection.

Question 65

what is used to evaluate test results

Answer 65

magnitude of the interruption

Question 66

A radiographic inspection uses radiation energy to detect variations in x-ray attenuation in the object under inspection and can detect inclusions, voids, cracks, and changes in geometry or material properties.

Answer 66

X-RAY OR RADIOGRAPHIC INSPECTIONS

Question 67

The aviation industry typically uses two types of radiation energy

Answer 67

x-rays and gamma rays

Question 68

are produced by electronic generators

Answer 68

x-rays

Question 69

are produced by isotope sources

Answer 69

gamma rays

Question 70

can be used to inspect most materials for both surface and internal flaws, but the orientation of the flaw and source is critical.

Answer 70

A radiographic inspection

Question 71

A two-dimensional image that can be immediately displayed on a viewing screen or television monitor.

Answer 71

REAL-TIME RADIOGRAPHY

Question 72

This technique converts unabsorbed radiation into an optical or electronic signal which can be viewed immediately or can be processed with electronic or video equipment.

Answer 72

REAL-TIME RADIOGRAPHY

Question 73

a two dimensional latent image from the projected radiation is produced on a sheet of film or paper that has been exposed to the unabsorbed radiation passing through the test piece.

Answer 73

film or paper radiography

Question 74

This technique requires subsequent development of the exposed film or paper so that the latent image becomes visible for viewing.

Answer 74

film or paper radiography

Question 75

what can be detected and measured via digital radiography

Answer 75

-Uniform corrosion -Erosion corrosion -Corrosion under insulation (CUI) -Corrosion under pipe supports -Welding corrosion

Question 76

Via ultrasonic inspection following defects can be detected:

Answer 76

-cracks in the weld zone; pores; -lack of fusion in welded joints; -stratification of weld metal; -discontinuities and incomplete fusion of weld joints; -slack metal in the lower zone of the weld; -areas which are affected by corrosion; -areas with the mismatch of chemical composition; -areas with distortion geometric size.