familiarization about NDT

1. 3

2. Appraisal of NDT Methods and their Application in Aviation
4

3. o Intro - Lt Col Khalid
o Visual & Dye-penetrant Testing - Mr Latif
o Magnetic Particle Testing - F/L Rida
o Ultrasonic & Eddy Current Testing - F/L Amim
o Radiographic Testing - F/L Asad
o Recoms - Lt Col Khalid
Sequence

4. To present appraisal of NDT methods and their application in
Aviation
Aim

5. INTRO
Overview

6. INTRO
Overview
Combination of atoms
Different composn
Shape,size,chemical/physical/thermalproperties

7. INTRO
Overview

8. INTRO
Overview
Voids

9. INTRO
Overview

10. INTRO
Overview
Loading
StressConc
Corrosion
Heat

11. FAILURE
Overview
Definition: Part doesn’t function as designed
Minor Major
Any failure is UNACCEPTABLE

12. Nondestructive Testing (NDT)
NDT
5
4
Insp or measure without doing harm

13. Nondestructive Testing (NDT)
NDT
5
4

14. TECHNIQUES
1 VISUAL
6 RADIOGRAPHY
NDT
2 DYE PENETRANT
5 ULTRASONIC
3 MAGNETIC PARTICLE
4 EDDYCURRENT
Common NDT Techniques

15. Visual Inspection

16.  General
 Visual inspection is the oldest methods of NDT testing
 It is a quick and economical method of detecting various types of
cracks before they progress to failure
 Defects that would otherwise escaped the necked eye can often be
detected with the aid of optical devices because
 They magnify defects that could not be seen by the unaided eyes
 They permit visual insp of areas that are not accessible to unaided eye
VISUAL INSP

17.  The equipment necessary for conducting a visual inspection usually
consists of the following:-
o Strong Flashlight
o Mirror with a Ball Joint
o 2.5 x -4 Magnifying Glass
VISUAL INSP AID

18. VISUAL INSP AID

19.  Before attempting a close, visual inspection of any selected part or
structural area, it should be checked for signs of corrosion
 Any corrosion found, should be tested to discover its extent and
severity
CORROSION TREATMENT

20.  The first step in a visual insp should be an examination of the area for
deformed or missing fasteners
 These should be identified for subsequent replacement
 A close examination for cracks in the surfaces of structural members
should be made with the aid of a flashlight
STRUCTURAL FAILURE DETERMINATION

21.  Cleaning of Structural Parts
All part of areas from which mild corrosion has been removed should be
thoroughly cleaned using an approved solvent
 All Other Areas to be Inspected
All other areas to be inspected should also be cleaned of any deposits
that might hinder the discovery of existing surface flaws
STRUCTURAL FAILURE DETERMINATION

22.  Crack Detection Technique
When looking for surface cracks, the inspector should point his flash
light towards himself and hold it at an angle of 5o – 45o to the surface
 Verification of Cracks
A 10 x magnifying glass may be used to confirm the existence or extent
of a suspected crack
STRUCTURAL FAILURE DETERMINATION

23.  Bore Scopes
 Bore scope is a precision optical inst with a built-in light source.
Bore scopes are specialized form of telescopes and are avail in
numerous models from 10 inch diameter and a few inches long to
diameters less than 0.75 inch and several feet long
 Short length bore scopes with large diameters yield the brightest
images
STRUCTURAL FAILURE DETERMINATION

24.  Advantages
 Cheapness
 Portability
 Immediate results
 Minimum special skill
 Minimum part preparation
ADVANTAGE /DISADVANTAGE

25.  Disadvantages
 Suitable only for surfaces which can be viewed
 Generally detects only larger defects
 Misinterpretation of cracks and scratches
ADVANTAGE /DISADVANTAGE

26.  General
 Dye penetrant inspection is used to detect small surface crack which
can not be found by normal visual inspection
 Dye penetrant inspection may be used with out limitation on most
aircraft material and will give positive indication or any type of
structure
 The method depends upon the ability of high penetrating liquid to
seem the discontinuity in the material
 It will indicate the surface opening or accessible
DYE PENETRANT INSP

27.  Pre Maint Req
 Penetration kit which include following
o Cleaner
o Penetrant (Red Color)
o Developer (White Color)
 Soft cotton rag
 Magnifying glass
 Surface must be cleaned thoroughly
DYE PENETRANT INSP

28. • The material surface which is req to be insp must be free
from dust, lubricants and paints.
• Note. The Penetrant should never be use exceeding temp 120° F. It
is highly flammable solvent.
DYE PENETRANT INSP

29. DYE PENETRANT INSP

30.  Procedure
 Apply the cleaner on the surface
 Apply penetrant and permit it 20 minutes for soaking
 Apply cleaner on cotton rag and semi wet cotton rag to use to
remove excessive solvent from surface
 After 10 min apply developer to improve the flaw/ crack
 Distance b/w developer and surface should be 2 inch
 Remove developer from surface after four hrs
DYE PENETRANT INSP

31.  Advantages
 Cheapness
 Portable
 High sensitivity
 Immediate result
ADVANTAGE /DISADVANTAGE

32.  Disadvantages
 Can only be inspect surface of parts accessible to penetrant
application
 Defect must be open to surface
 Part preparation, such as removal of finishes and sealant req
ADVANTAGE /DISADVANTAGE

33.  General
• It is suitable for the inspection of most
o Metal
o Plastic and
o Ceramics for surface and sub-surface defect.
• The inspection of air frame structure is accomplished by inducing
the ultra sound into the part by connecting probe and picking up
reflection of this sound from with in the part detected ultra sonic
reflection.
ULTRASONIC INSP

34. ULTRASONIC INSP

35.  Advantages
 Suitable for surface and sub-surface defect
 Sensitive to small defects
 Immediate test result
 Little part preparation
 Wide range of material thickness can be inspected
 Portable
ULTRASONIC INSP

36.  Disadvantages
 Surface of part being inspected must be accessible to ultrasonic
probe
 Rough surface interferes with test result
 Test method is directional depending on sound beam
 High degree of skill and experience required to set up an inter part
result
 No permanent test records
ULTRASONIC INSP

37.  General
 Eddy current insp is a NDT means for detecting discontinuities in a
part
 To initiate eddy current in a part an alternating current at a suitable
freq is supplied to the test coil
 The coil carrying this current in turn induces a magnetic field of the
same freq in the part and causes eddy current to flow
EDDY CURRENT INSP

38.  Variation in the magnitude of eddy current will effect this
magnetic field and when analyzed electronically will give
information regarding structural change in the part such as
discontinuities, thickness alloy or heat treat of material
EDDY CURRENT INSP

39. EDDY CURRENT INSP

40.  Equipment Required
 Inner probe
 Outer probe
 Electronic tester
EDDY CURRENT INSP

41.  Preparation of Parts
 Surface requires good contact with the probe
 Part needs no preparation
 Corroded parts need light rubbing with cloth
 The part being inspected must be clean thoroughly
EDDY CURRENT INSP

42.  Insp Procedure
 The surface of the area being inspected must be thoroughly
cleaned so the eddy current probe can make good contact
 Dirt, carbon or grease deposits must be cleaned
 Using the surface probe work back and forth over suspected area
or using the internal probe rotate inside the hole and work up and
down the wall
EDDY CURRENT INSP

43.  When a damage area encountered such as a cracks, corrosion etc
the meter needle will suddenly deflect
 By working the probe around the area and observing meter
needle deflection
 It will possible to obtained an accurate location of the damaged
area which can be marked
EDDY CURRENT INSP

44.  Advantages
o Portable
o Moderate cost
o Immediate results
o Sensitive to small indication
o Little part preparation
EDDY CURRENT INSP

45.  Disadvantages.
oSuitable for inspection of metal parts only.
oPart must be accessible.
oNo permanent test record.
oRequired skill level.
oRough surface interferes with test sensitivity.
EDDY CURRENT INSP

46.  General
 Magnetic particle insp is a method of detecting cracks or other
flaws on the surface
 Subsurface or materials that are readily magnetized
 This type of insp will generally find usage with steel fasteners
 Landing gear components and a few steel fittings such as found in
engine or empennage attach fittings
MAGNETIC PARTICLE INSP

47.  Magnetic Fields
 Magnetic fields are induced in Ferro magnetic parts when exposed
to an electric current or field of the current
 By controlling the direction of the magnetizing current, the lines of
magnetic force can be induced at right angles to the discontinuity
 Direction of the magnetic field is critical
MAGNETIC PARTICLE INSP

48.  Magnetic particle inspection will provide excellent indications of all
surface discontinuities provided the part is free from greases, oil
dirt or lose scale or surface finish
 This type of insp generally apply to parts which are disassembled
 The lines of force should be at right angles to the longest dimension
of the discontinuity if the best results are req
MAGNETIC PARTICLE INSP

49. MAGNETIC PARTICLE INSP

50.  A gen rule for magnetic field orientation is the right hand rule
 This rule states that if your grasp the article being magnetized with
your right hand so that your thumb points in the direction of current
flow the lines of force in the magnetic field will be represented by
your four fingers
MAGNETIC PARTICLE INSP

51.  Methods for applying magnetic fields to parts for insp
 Fol are the common method used for insp
• Longitudinal magnetism
• Circular magnetism
• Magnetic particles
• Wet particles
• Dry particles
• Crack indications
MAGNETIC PARTICLE INSP

52.  Advantages
 Semi portable
 Sensitive to small indications
 Detects surface and near surface defects
 Sensitive to inclusions as well as cracks
 Moderate skill required to perform
MAGNETIC PARTICLE INSP

53.  Disadvantages
 Only suitable for Ferro-magnetic material
 Part must be physically and visually accessible for test
 Removal of most surface coatings and sealant req
 Insp is semi directional requiring a general orientation of field to
detect
MAGNETIC PARTICLE INSP

54.  No permanent test results unless indications from dry powder
technique are recorded by pressing “scotch” tape on the surface.
 Not usable in area where a strong magnetic field may damage
instruments.
 Part must be demagnetized after insp
MAGNETIC PARTICLE INSP

55.  General
 It is very useful to detect sub surface and internal cracks. It can be
applied on aircraft or parts of aircraft as well
Radio Graphic Inspection

56.  Precaution
 De-fuel the ac
 Electrical power should be switched off
 Protect avionic equipment
 Rope the aircraft and place caution boundary
 Only qualified and authorized personal are authorized to carry out
this inspection
Radio Graphic Inspection

57.  Procedure
 The x- rays and gamma rays passes into the part produce film
 These rays travel directionally, the gamma rays produce by isotope
machine and X rays are produce by compartment suitable target by
electrons produce in a vacuum by the application of high voltage
GraRadiophic Inspection

58.  Advantages
 Suitable for surface and sub surface crack
 Ability to aspect the part
 Cover or hidden by other part
 Permanent test record
 Minimum part preparation required
Radio Graphic Inspection

59.  Disadvantages
 Air craft must be de-fuelled
 Test method is highly directional
 Area must be out of bound for other personnel
X-RAY INSP