End of Chapters, FAA Questions, Exam Review, Kahoots

What is Nondestructive Testing (NDT)?

Nondestructive Testing (NDT) is inspection that does not require the disassembly or destruction of a part to verify its integrity.

What visual inspection tools can be used along with other NDT techniques?

Flashlights, mirrors, scopes, and other tools are used along with techniques like liquid penetrant and magnetic particle inspection.

What tools allow you to inspect inside engines and record visual images for later reference?

Borescopes, fiberoptic scopes, and video scopes allow you to inspect inside engines and can record the visual image of the inspected area.

What principle does liquid penetrant inspection work on, and what does it locate?

Liquid penetrant inspection works according to the principle of capillary attraction.
It helps locate cracks, porosity, or other faults that are open to the surface, using a penetrant material and a developer.

What is dwell time in liquid penetrant inspection?

Dwell time is the time required for the penetrant used in the inspection to cure.

How does magnetic particle inspection work, and what materials is it used on?

Magnetic particle inspection is most often used for iron or iron alloy materials.

It involves magnetizing the part and then spraying it with an oxide containing magnetic particles.

The particles align with disruptions in the magnetic field created by discontinuities in the material.

What types of current are used for magnetization in magnetic particle inspection?

Direct current (DC), half-wave rectified DC, and alternating current (AC) are all used in magnetic particle inspection.

Why are iron oxides in magnetic particle inspection treated with a dye, and what does it affect?

The iron oxides are treated with a dye to cause them to fluoresce under ultraviolet light.

The color of the dye determines whether you use a white light or a black light during inspection.

What must be done after a part is inspected using magnetic particle inspection?

The part must be demagnetized before returning it to service.

Nondestructive Testing (NDT) Definition

A method of inspection preformed without the disassembly or destruction of the part or structure.

Borescope Definition

A optical tool with which a visual inspection can be made inside an area that is otherwise impossible to see. It consists of light, mirrors and lenses

Liquid Penetration Inspection Definition

A nondestructive inspection technique used to locate crakes, porosity, or other faults open to the surface using the principle of capillary attraction

Capillary Attraction Definition

An action causing a liquid to be drawn up into extremely tiny tubes or between close-fitting parts.

Dwell Time Definition

The time required for a liquid penetrant to cure based on the size and shape of the discontinuity

1. A ____________ is an optical device that allows us to see inside an engine without disassembling it.

borescope

2. The ____________ borescope uses a bundle of optical glass fibers.

fiberoptic

3. A ______________________ provides a high quality video image that can be recorded for reference.

Video Scope

4. Liquid penetrant inspection may be used to detect discontinuities that are _____________ (open to or below) the surface.

open to

5. Penetrant inspection is based on the principle of ____________ attraction.

capillary

6. A fault located with the fluorescent penetrant method will show up as a ____________ (red or green) line.

green

7. Parts which are to be inspected using liquid penetrants ___________ (should or should not) be cleaned with an abrasive blast.

should not

8. The time the penetrant remains on the surface of the part is known as the ____________ time.

dwell

9. There are three types of penetrants used for liquid penetrant inspection. They are:

a. ____________
b. ____________
c. ____________

a. water-soluble
b. post-emulsified
c. solvent-removable

10. Three types of developers that may be used with the liquid penetrant inspection method are:

a. ____________
b. ____________
c. ____________

a. dry
b. wet
c. non-aqueous

11. The two methods of testing by magnetic particle inspection are:

a. ____________
b. ____________

a. continuous
b. residual

12. Magnetic particle inspection may be used on ____________ metal parts.

ferrous

13. The magnetism that remains in a material after the magnetizing force is removed is known as ____________ magnetism.

residual

14. The ability of a material to retain magnetism after the magnetizing force is removed is called ____________.

retentivity

15. The ease with which a material can conduct lines of magnetic flux is called its ____________.

permeability

16. When magnetizing a part for magnetic particle inspection, it must be magnetized in such a way that the lines of flux are ____________ (parallel or perpendicular) to the suspected fault.

perpendicular

17. Two methods of magnetization for mag particle inspection are ____________ and ____________.

a. longitudinal
b. circular

18. When a part is placed between the heads of the magnetizing machine and current flows through the specimen, the part is magnetized by the ____________ method.

circular

19. When the part is placed in a coil through which the magnetizing current flows, the part is magnetized by the ____________ method.

longitudinal

20. The three types of electrical current that may be used to magnetize a part for inspection are:

a. ____________
b. ____________
c. ____________

a. alternating current
b. direct current
c. half-wave rectified current

21. AC magnetization is best suited for locating ____________ (surface or sub-surface) faults.

surface

22. Two important characteristics of the testing medium used for magnetic particle inspection are:

a. ____________ (high or low) permeability
b. ____________ (high or low) retentivity

a. high
b. low

23. After the part has been inspected using the mag particle inspection method it must be ____________ before returning it to service.

demagnetized

What is the advantage of electronic inspection techniques over visual inspection?

They allow viewing of a structure’s interior that visual inspection cannot provide.

What can eddy current inspection detect and how much prep is required?

It detects surface and subsurface flaws in most metals with little or no part preparation. It also determines how easily a material accepts induced current (i.e., how conductive the material is).

What are the two methods of eddy current inspection?

1. Absolute method – zeros to a standard piece of material.

2. Comparison method – shows difference between probe and test material.

What materials can ultrasonic inspection be used on?

Plastics, ceramics, and metals.

What are the two basic systems in ultrasonic inspection?

Pulse-echo and resonance.

What does ultrasonic test equipment measure and why is it useful?

It measures material thickness, helping to inspect for corrosion inside structures.

What does radiographic inspection provide?

A photographic view inside a structure using electromagnetic spectrum imaging.

Why are magnetic particle and liquid penetrant not effective for composites?

They don’t work well on composites; other methods are better.

What NDT methods are used for inspecting composites? (List 4)

Laser holography, shearography, thermography, and tap testing.

What is computer-aided tap testing?

A new NDT method that uses a computer system (not just software) to interpret coin tap testing results for composite materials.

How is ultrasonic testing used with composites?

For quality checks and NDT during manufacturing and technician inspections.

What is coin tap testing and what is it best for?

It’s a simple and effective method to test laminated, bonded, and honeycomb composites.

Conductivity Definition

The characteristic of a material that makes it possible for it to transmit heat or electrical energy by conduction.

Dosimeters Definition

A radiation-monitoring badge worn by persons working around x-ray or gamma ray equipment. These badges are periodically checked to determine the possibility of abnormally high radiation exposure.

Also known as Radiation monitoring film badge.

Ground State Definition

The lowest energy state a given atom can have.

Isotope Definition

An atom that has the same atomic number as a chemical element, but a different atomic mass and different physical properties.

Longitudinal Waves Definition

Waves within an elastic material in which the particles in motion move back and forth, parallel to the direction the wave is traveling.

Permeability Definition

The ability of a material to accept and concentrate line of magnetic flux.

Pulse-Echo System Definition

A system of ultrasonic nondestructive inspection used to detect the presence of internal damage or fault in construction material.

Radiation Monitoring Film Badges Definition

Also known as dosimeter.

Rayleigh Waves Definition

Waves that travel along the surface of the material but do not appreciably extend into a material.

Also called surface waves.

Resonance System Definition

A system of ultrasonic nondestructive inspection used to detect the presence of vibration that in exactly the same as the natural vibration frequency of a structure.

Shear Waves Definition

A wave in which the particles vibrate at right angle to the direction of the wave.

Also referred to as transverse wave.

Surface Waves Definition

Shear waves that travel along the surface of a material but do not appreciably extend into a material.

Also called Rayleigh waves.

Transducers Definition

An electrical device that either takes electrical energy and changes into mechanical movement or takes mechanical movement and changes is it into electrical energy.

Transverse Waves Definition

A wave in which the particles vibrate at right angle to the direction of the wave.

Also called Shear wave.

1. The four properties of a metal that makes eddy current inspection possible are:
  a. ____________________________

  b. ____________________________

  c. ____________________________

  d. ____________________________

a. conductivity

b. permeability

c. mass

d. presence of faults

2. What are the two methods of inspection that utilize eddy current principles?
  a. ____________________________

  b. ____________________________

a. absolute

b. comparison

3. Ultrasonic waves that are used for nondestructive inspection vary in frequency from ______ kilohertz to ______ megahertz.

200, 25

4. A ________________ material is one that will produce an electrical potential when it is pressed, bent, or otherwise distorted.

piezoelectric

5. The three types of waves that can be introduced into a test specimen when using ultrasonic inspection are:
  a. ____________________________

  b. ____________________________

  c. ____________________________

a. longitudinal

b. transverse

c. surface

6. The two types of radiation energy (rays) used for radiographic inspection are:
  a. ____________________________

  b. ____________________________

a. x-ray

b. gamma ray

7. The __________ (voltage or current) supplied to the anode of an X-ray tube determines the energy of an X-ray.

voltage

8. The __________ (voltage or current) supplied to the cathode of an X-ray tube determines the intensity of an X-ray.

current

9. Gamma rays are produced by the disintegration of certain ____________________________.

isotopes

10. The factors that determine the proper exposure for radiographic inspection include, but are not limited to:
  a. ____________________________

  b. ____________________________

  c. ____________________________

  d. ____________________________

  e. ____________________________

  f. ____________________________

  g. ____________________________

  h. ____________________________

a. Material thickness and density

b. Shape and size of the object

c. Type of defect to be detected

d. Characteristics of the equipment used

e. Exposure distance

f. Exposure angle

g. Film characteristics

h. Types of intensifying screen, if used

11. The image formed on the photographic film by either X-rays or gamma-rays is a __________ (positive or negative) representation of the specimen being inspected.

negative

12. Persons working around X-ray or gamma-ray equipment should wear __________ film badges.

monitoring

13. Though simple, a __________ __________ __________ is one of the most effective methods of composite inspection.

coin tap test

11-1
Magnetic particle inspection is used primarily to detect:

A– distortion.
B– deep subsurface flaws.
C– flaws on or near the surface.

C– flaws on or near the surface.

Because the magnetic fields generated within a material are weak, magnetic particle inspection is primarily used to detect surface flaws in ferromagnetic materials such as iron and steel. The magnetic field produced by distortions and deep subsurface flaws are typically not strong enough to attract the indicating medium.

11-2
Liquid penetrant inspection methods may be used on which of the following?

1. Porous plastics

2. Ferrous metals

3. Nonferrous metals

4. Smooth primer-sealed wood

5. Nonporous plastics

---

A– 2, 3, and 4
B– 1, 2, and 3
C– 2, 3, and 5

C– 2, 3, and 5

Penetrant inspection is an effective nondestructive testing method for detecting defects that are open to the surface in materials such as ferrous metals, nonferrous metals, and nonporous materials. Even if the defects are too small for visual or other methods of detection, as long as the defect is open to the surface, dye penetrant inspection is effective. The magnetic characteristics of the material being checked have no bearing as to the effectiveness of dye penetrant inspection.

11-3
What method of magnetic particle inspection is used most often to inspect aircraft parts for invisible cracks and other defects?

A– Residual
B– Inductance
C– Continuous

C– Continuous

In the continuous method of magnetic particle inspection, a part is magnetized and the indicating medium applied while the magnetizing force is maintained. The continuous method is used in practically all circular and longitudinal magnetization procedures because it provides greater sensitivity than the residual method, particularly in locating subsurface defects.

11-4
The testing medium that is generally used in magnetic particle inspection utilizes a ferromagnetic material that has:

A– high permeability and low retentivity.
B– low permeability and high retentivity.
C– high permeability and high retentivity.

A– high permeability and low retentivity.

In addition to being ferromagnetic, and finely divided, the testing medium used in magnetic particle inspection must conduct lines of magnetic flux easily (high permeability), and not retain a high degree of magnetism after the magnetizing current is removed (low retentivity).

11-5
Which statement relating to the “residual magnetizing inspection” method is true?

A– Subsurface discontinuities are made readily apparent.
B– It is used in practically all circular and longitudinal magnetizing procedures.
C– It may be used only with steels which have been heat treated for stressed applications.

C– It may be used only with steels which have been heat treated for stressed applications.

The residual inspection procedure is used only with steels which have been heat treated for stressed applications. The continuous magnetizing inspection method is used on almost all circular and longitudinal magnetizing procedures. In either case, subsurface discontinuities are not made apparent using either method.

11-6
What two types of indicating mediums are available for magnetic particle inspection?

A– Wet and dry process materials
B– High retentivity and low permeability material
C– Iron and ferric oxides

A– Wet and dry process materials

Magnetic particle inspection media are either wet or dry process materials. The dry process uses iron oxide powder poured or sprayed on the part being tested. The wet process requires mixing the oxide powder with kerosene or some other light oil. The part being inspected is then immersed in the oxide-oil bath. High retentivity and low permeability material is incorrect because the media used in magnetic particle inspection must have a low retentivity and a high permeability.

11-7
Which of the following materials may be inspected using the magnetic particle inspection method?

1. Magnesium alloys

2. Aluminum alloys

3. Iron alloys

4. Copper alloys

5. Zinc alloys

---

A– 1, 2, and 3
B– 1, 2, 4, and 5
C– 3

C– 3

Magnetic particle inspection is limited to use on ferromagnetic materials such as iron and steel. Alloys containing primarily magnesium or aluminum are non-magnetic and, therefore, cannot be inspected using magnetic particle inspection.

11-8
One way a part may be demagnetized after magnetic particle inspection is by:

A– subjecting the part to high voltage, low amperage AC.
B– slowly moving the part out of an AC magnetic field of sufficient strength.
C– slowly moving the part into an AC magnetic field of sufficient strength.

B– slowly moving the part out of an AC magnetic field of sufficient strength.

If a part is subjected to an AC magnetizing force and then slowly removed from the force while the current is still flowing, the domains within the material become disorganized and magnetism decreases.

11-9
Which type crack can be detected by magnetic particle inspection using either circular or longitudinal magnetization?

A– 45°
B– Longitudinal
C– Transverse

A– 45°

In order to locate a defect using magnetic particle inspection, it is essential that the lines of flux pass approximately perpendicular to the defect. Circular magnetization locates defects running approximately parallel to the axis of the part, while longitudinal magnetization locates defects running approximately 90° to the axis. If a defect is 45° to the axis of the part, either method should detect it.

11-10
Which of the following methods may be suitable to use to detect cracks open to the surface in aluminum forgings and castings?

1. Dye penetrant inspection

2. Magnetic particle inspection

3. Metallic ring (coin tap) inspection

4. Eddy current inspection

5. Ultrasonic inspection

6. Visual inspection

---

A– 1, 4, 5, and 6
B– 1, 2, 4, 5, and 6
C– 1, 2, 3, 4, 5, and 6

A– 1, 4, 5, and 6

If a crack is open to the surface on an aluminum forging, the crack can be detected through the use of dye penetrant, eddy current, ultrasonic, or visual inspections. Magnetic particle inspection is incorrect because it can only be used on ferrous metals and aluminum is not a ferrous metal. In addition, the metallic ring, or coin tap inspection is used primarily on composite structures.

11-11
To detect a minute crack using dye penetrant inspection usually requires:

A– that the developer be applied to a flat surface.
B– a longer-than-normal penetrating time.
C– the surface to be highly polished.

B– a longer-than-normal penetrating time.

Dye penetrant inspection is based on capillary attraction. In other words, dye is drawn into a crack or defect until developer is applied making the defect visible. A good rule to remember when using dye penetrant is that small defects require a longer penetrating time.

11-12
When checking an item with the magnetic particle inspection method, circular and longitudinal magnetization should be used to

A– reveal all possible defects.
B– evenly magnetize the entire part.
C– ensure uniform current flow.

A– reveal all possible defects.

Circular magnetization reveals defects running approximately parallel to the axis of the part, while longitudinal magnetization reveals defects that are approximately 90° to the axis. For this reason, it is best to use both methods to reveal all possible defects.

11-13
In magnetic particle inspection, a flaw that is perpendicular to the magnetic field flux lines generally causes:

A– a large disruption in the magnetic field.
B– a minimal disruption in the magnetic field.
C– no disruption in the magnetic field.

A– a large disruption in the magnetic field.

When performing a magnetic particle inspection, defects that are perpendicular to the lines of flux are more easily detected because the flaw produces a large disruption in the magnetic field. A minimal disruption in the magnetic field is incorrect because defects that are parallel, not perpendicular, to the flux lines cause minimal disruptions in the magnetic field. No disruption in the magnetic field is wrong because, if a flaw exists perpendicular to the magnetic field, a disruption will exist.

11-14
If dye penetrant inspection indications are not sharp and clear, the most probable cause is that the part:

A– was not correctly degreased before the developer was applied.
B– has no appreciable damage.
C– was not thoroughly washed before the developer was applied.

C– was not thoroughly washed before the developer was applied.

It is very important to remove all excess penetrant from the surface of a part at the completion of the dwell time. Any remaining penetrant on the part may result in indications that are not clear, or are completely masked by the background indication.

11-15

1. An aircraft part may be demagnetized by subjecting it to a magnetizing force from alternating current that is gradually reduced in strength.

2. An aircraft part may be demagnetized by subjecting it to a magnetizing force from direct current that is alternately reversed in direction and gradually reduced in strength.

---

Regarding the above statements,

A– both No. 1 and No. 2 are true.
B– only No. 1 is true.
C– only No. 2 is true.

A– both No. 1 and No. 2 are true.

By introducing a part to a decreasing, alternating magnetic field, the magnetic poles constantly change direction as their strength decreases. This is continued until the part is no longer magnetized. Reversing the polarity of direct current makes it functionally the same as alternating current.

11-16
The pattern for an inclusion is a magnetic particle buildup forming:

A– a fernlike pattern.
B– a single line.
C– parallel lines.

C– parallel lines.

Inclusions are nonmetallic materials, such as slag, that have been trapped in a material. Large inclusions near the surface or open to the surface usually appear elongated or as parallel lines.

11-17
A part which is being prepared for dye penetrant inspection should be cleaned with:

A– a volatile petroleum-base solvent.
B– the penetrant developer.
C– water-base solvents only.

A– a volatile petroleum-base solvent.

The success of a penetrant inspection depends a great deal on the cleanliness of the part being tested. Pre-cleaning with vapor degreaser or a volatile petroleum base solvent is a necessary step. Many penetrant kits provide an aerosol can of cleaning solvent to be used before and after testing. Water-base solvents are typically not used for cleaning parts since they are not that effective on grease.

11-18
Under magnetic particle inspection, a part will be identified as having a fatigue crack under which condition?

A– The discontinuity pattern is straight.
B– The discontinuity is found in a nonstressed area of the part.
C– The discontinuity is found in a highly stressed area of the part.

C– The discontinuity is found in a highly stressed area of the part.

Fatigue cracks are found in the highly stressed areas of a part, or where a stress concentration exists. The discontinuity pattern is straight is incorrect because, fatigue cracks offer clear, sharp patterns which are generally uniform and jagged in appearance.

11-19
In performing a dye penetrant inspection, the developer

A– seeps into a surface crack to indicate the presence of a defect.
B– acts as a blotter to produce a visible indication.
C– thoroughly cleans the surface prior to inspection.

B– acts as a blotter to produce a visible indication.

The principle action of the developer is to "blot" or draw the penetrant out of a defect making the defect visible. It seeps into a surface crack to indicate the presence of a defect is incorrect because it is the penetrant, not the developer, that seeps into a surface crack to indicate the presence of a defect. It thoroughly cleans the surface prior to inspection is wrong because surface cleaning is left to a volatile petroleum-based solvent, not the developer.

11-20
What defects will be detected by magnetizing a part using continuous longitudinal magnetization with a cable?

A– Defects perpendicular to the long axis of the part.
B– Defects parallel to the long axis of the part.
C– Defects parallel to the concentric circles of magnetic force within the part.

A– Defects perpendicular to the long axis of the part.

In longitudinal magnetization, a magnetic field is produced that is parallel to the axis of the part. This type of magnetization detects faults that are perpendicular to the axis of the part. Defects parallel to the long axis of the part and to the concentric circles of magnetic force within the part are wrong because the lines of flux generated must intersect a defect at nearly a 90 degree angle.

11-21
Circular magnetization of a part can be used to detect which defects?

A– Defects parallel to the long axis of the part.
B– Defects perpendicular to the long axis of the part.
C– Defects perpendicular to the concentric circles of magnetic force within the part.

A– Defects parallel to the long axis of the part.

Circular magnetization is obtained by passing the current through the part, and indicates defects that are parallel to the axis of the part. Defects perpendicular to the long axis of the part and to the concentric circles of magnetic force within the part are wrong because the magnetic flux lines must intersect a defect at nearly a 90 degree angle.

11-22
1. In nondestructive testing, a discontinuity may be defined as an interruption in the normal physical structure or configuration of a part.

2. A discontinuity may or may not affect the usefulness or a part.

---

Regarding the above statement:
A– only No. 1 is true.
B– only No. 2 is true.
C– both No. 1 and No. 2 are true.

C– both No. 1 and No. 2 are true.

A discontinuity may be defined as an interruption in the normal physical structure or configuration of a part such as a crack, inclusion, seam, or change in cross-sectional area. A crack or inclusion would affect the usefulness of the part. However, a seam or change in the cross-sectional area would not affect the usefulness of the part.

11-23
Which of the following is a main determinant of the dwell time to use when conducting a dye or fluorescent penetrant inspection?

A– The size and shape of the discontinuities being looked for.
B– The size and shape of the part being inspected.
C– The type and/or density of the part material.

A– The size and shape of the discontinuities being looked for.

To find cracks open to the surface using a dye penetrant inspection requires the penetrant be drawn into the crack by capillary action. Small cracks require longer dwell times for the penetrant to be drawn into the crack.

11-24
Holes and a few projecting globules are found in a weld. What action should be taken?

A– Thoroughly clean the area and reweld over the first bead to fill gaps and obtain uniform strength.
B– Remove all the old weld and reweld the joint.
C– Grind the rough surface smooth and reweld the joint.

B– Remove all the old weld and reweld the joint.

When checking the condition of a completed weld, there should be no signs of blowholes, porosity or projecting globules. If there is, the weld should be completely removed and the joint rewelded.