4. • Organogram:
Managing Director and CEO
Director Engineering an d
Material Management
Chief Engineer (Engineering
Production)
Principal
engineer
MCC
Deputy Cheif
Engineer
(Base
maintenance)
Deputy Cheif
Engineer (line
maintenance)
Deputy chief
Engineer
(component)
manager
hanger
complex
Principal
engineer- IFE
6. • NDT section of Base Maintenance
organogram:
• Engineer officer (In charge NDT Shop)
• Engineer Officer
• Junior Inspection officer
• Mechanic
7. • Nondestructive testing (NDT) is the
examination of an object or material without
destroying.
• It is a wide group of analysis techniques used
in science and industry to inspect, test or
evaluate the properties of a material,
component or system without causing
damage.
8. Why NDT is important in aviation
section?
• To look for internal changes
• To look for signs of wear or fatigue in aircraft
structure
• To find internal damage or discontinuities
9. Common NDT methods
1. Liquid penetrant Inspection
2. Magnetic particle Inspection
3. Eddy current Inspection
4. Ultrasonic Inspection
5. Radiography (x-ray/gamma ray) Inspection
10. Liquid penetrant Inspection
• Clean and dry the surface of the component
• Apply penetrant
• Remove access penetrant
• Apply developer
• Reveal the flaw pattern under white light or
ultraviolet light
• Visual inspection
• Post clean component
• Crack reporting
11. • Advantages:
• Provide visual evidence cracks, porosity, laps,
seams of other surface discontinuities rapidly
• Economically reliable
• Easily portable
• Can be used on aircraft or in the workshop.
• Fairly simple method
• Sensitive to fine, tight discontinuities
12. Limitations:
• Can detect non porus surface discontinuity
only
• Difficult to use on very rough surface
• No easy method to produce permanent record
13. Magnetic Particle Inspection
• Component pre-cleaning
• Introduction to magnetic field
• Examine the test object under suitable lighting
conditions
14. Advantages:
• Quantitative
• Can be automated, apart from viewing
• Simplicity of operation and application
• Easily portable
• It is quicker
15. • Limitations:
• 1. Restricted to ferromagnetic materials
• 2. Restricted to surface or near surface flaws
• 3. Not fail safe in the lack of indication could
mean no defects or process not carried out
properly
16. Eddy Current
• Eddy currents are electrical currents induced in a
conductor by alternating magnetic field.
• Eddy currents are circular
• Oriented perpendicular to the direction of the applied
magnetic field.
• The
a) electrical conductivity
b) magnetic permeability
c) geometry and
d) homogeneity of the test object
all affects the induced currents
17. • Changes in the geometry & homogeneity of
the test object will change the magnitude &
distribution of the eddy currents.
• By monitoring these changes, the presence of
cracks & other flaws can be detected.
18. • Advantages:
• Does not require couplant.
• Gives instantaneous response
• Is very repeatable
• Accurate for dimensional analysis of flaws
• Extremely sensitive to flaws
19. • Limitations:
• Applied for conductive material only
• Depth of penetration is limited
• Lack of proper calibration of machine may
occur error in crack detection
20. Ultrasonic Inspection
• High frequency sound waves are introduced
into a material
• They are reflected back from surfaces or flaws
• Reflected sound energy is displayed versus
time
• Thus from the reading discontinuities are
detected
21. Ultrasonic inspection is usually performed with
two techniques:
• Reflection or “Pulse echo” technique
• Through transmission technique. 'Pulse echo'
technique is most widely used in aircraft
maintenance inspection
22. Advantages:
• Thickness and length up to 30 ft can be tested
• Position, size, type of the defect can be
determined
• Instant test result
• Portable
• Extremely sensible if required
• No consumables
• Capable of being fully automated
23. Limitations:
• No permanent record available
• The operator can decide whether the test piece is
defective or not while the test is in progress
• Indications require interpretation
• Considerable degree of skill is necessary to obtain
the fullest information from the test
• Very thin section can prove difficult
24. Radiographic Inspection
• One of the oldest and widely used nondestructive
testing methods
• Electromagnetic radiation such as x-rays or gamma rays
is passed through an object onto a film.
• An invisible change called a 'latent image' is produced
in film emulsion
• The areas so exposed become darker when the film is
immersed in a developing solution
• The film is next put into a fixing bath to remove the
fixer
• Finally dried for interpretation and record
25. • Advantages:
• 1. It is used to inspect a variety of nonmetallic
parts
• 2. Excellent for detecting internal
discontinuities
• 3. Beam direction unaffected by part
geometry
• 4. No calibration required
26. • Disadvantages:
• 1. Radiation hazard
• 2. Limited depth penetration
• 3. Access to both side required
• 4. Orientation limitations
27. Conclusion
• We have discussed on five common NDT
methods and their advantages and limitations.
• We also have given a brief portrayal of Base
maintenance section of Biman Bangladesh
Airlines.
