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Aircraft NDT
Aircraft Maintenance NDT Principles
Question | Answer |
---|---|
Which NDI method is considered quick, reliable, small level of skill, and inexpensive for detecting surface defects | Dye Penetrant Inspection |
This method cannot be used on materials with rough surfaces or highly absorbent such as rubber, plastics, or some synthetic materials | Dye Penetrant Inspection |
What are the two types of penetrant materials for dye penetrant inspection | visible dye and fluorescent dye |
After penetrant is applied it is set aside to drain, this is known as the... | penetration time or dwell time |
During a dye penetrant process, poor cleaning, poor developer removal , or press-fit parts generally result in... | False Indications |
A form of NDI that can detect flaws on the surface or just below the surface of alloys composed of iron or steel. | Magnetic Particle Inspection |
Iron, steel, cobalt, nickel and their alloys are considered ________ materials allowing them to be affected by magnetic particle inspection. | Ferromagnetic |
The ease with which a part can be magnetized | permeability |
What are the two methods of magnetic particle inspection | circular and longitudinal magnetization |
Proper orientation is critical to reveal defects, therefore, how should the magnetic field situated relative to a crack | Right angles are best |
Two methos used to perform circular magnetization | direct contact or direct induction and indirect or central conductor methods |
What is longitudinal magnetization used for? | circumferential discontinuities 45 to 90 degrees from the axis |
What is used to create longitudinal magnetization? | Coil shot |
What is used to create circular magnetization | Head shot |
Which current (AC or DC) is most able to detect subsurface discontinuities | DC |
Which magnetic particle inspection method uses magnetizing force that is active when the indicating method is applied. | continuous magnetization method |
How can magnetic particles be applied | Wet or Dry |
What are the methods of applying a penetrant for inspection? | Spraying, immersion, brushing |
Which method of nondestructive testing uses sound waves? | Ultrasonic |
Radiographic inspection can cause... | Genetic Mutations |
A part which is being prepared for dye penetrant inspection should be cleaned with... | A volatile petroleum base solvent |
What method of magnetic particle inspection is used most often to inspect aircraft parts for invisible cracks and other defects? | Continuous |
Which nondestructive testing method is suitable for inspecting most metals, plastics, and ceramics for surface and subsurface defects? | Ultrasonic |
The pattern for an inclusion in a magnetic particle inspection causes... | Parallel lines |
The testing medium that is generally used in magnetic particle inspection utilizes a ferromagnetic material that has... | High permeability and low retentivity |
Which type of magnetization may be used with steels that have been heat treated for stress applications? | Residual |
A mechanic has completed a bonded honeycomb repair using the potted compound repair technique. What NDT method is used to determine the soundness of the repair? | Metallic ring test |
What are the two types of indicating mediums available for magnetic particle inspection | Wet and dry process materials |
What is one way a part may be demagnetized after magnetic particle inspection? | Slowly moving the part out of an AC magnetic field of sufficient strength |
To detect a minute crack using dye penetrant inspection usually requires... | A longer-than-normal penetrating time |
Disadvantages : Detects only surface breaking defects. Surface preparation is critical as contaminants can mask defects. Requires a relatively smooth and nonporous surface. | Dye Penetrant |
Disadvantages: Surface must be accessible to probe and couplant. Skill and training required is more extensive than other technique. Surface finish and roughness can interfere with inspection. | Ultrasonic |
Disadvantages Only ferromagnetic materials can be inspected. Proper alignment of magnetic field and defect is critical. Large currents are needed for very large parts. | Magnetic Particle Testing |
Disadvantages:Only conductive materials can be inspected. Ferromagnetic materials require special treatment to address magnetic permeability. Depth of penetration is limited. | Eddy Current Testing |
Disadvantages: Extensive operator training and skill required. Access to both sides of the structure is usually required. Orientation of the radiation beam to non-volumetric defects is critical. | Radiographic Testing |
Advantages: Large surface areas or large volumes of parts can be inspected rapidly at low cost. Parts with complex geometry routinely inspected. Indications produced directly on surface of part providing a visual image of the discontinuity. | Dye Penetrant Testing |
Advantages: Large surface areas of complex parts can be inspected rapidly. Can detect surface and subsurface flaws. Surface preparation is less critical than it is in penetrant inspection. | Magnetic Particle Testing |
Advantages: Depth of penetration for flaw detection or measurement is superior to other methods. Only single sided access is required. Provides distance information. Minimum part preparation is required. | Ultrasonic Testing |
Advantages: Detects surface and near surface defects. Test probe does not need to contact the part. Method can be used for more than flaw detection. | Eddy Current Testing |
Advantages: Can be used to inspect virtually all materials. Detects surface and subsurface defects. Ability to inspect complex shapes and multi-layered structures without disassembly. Minimum part preparation is required. | Radiographic |