Non - Destructive Testing

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Non - Destructive Testing

Non-Destructive Testing is being carried out by the NDT Project Lead by using the latest technology products through a professional outlook under supervision of the Air Craft Maintenance Directorate in Turkish Airlines TURKISH TECHNIC Inc.

What is Non-Destructive Testing and Why is it Necessary?

Non-Destructive Testing (NDT) is a type of inspection that is carried out without harming the integrity of the material or part to be tested. Methods of Non-Destructive Testing are used in the determination of discontinuities (cracks, corrosion, structural disorders, etc.) on the surface or inside the material. Sectors wherein methods of Non-Destructive Testing are used are briefly; component manufacturing (forged and cast, automotive, aerospace (in repair/maintenance and component manufacturing), building-construction, bridge maintenance, pipe production, railways, industrial buildings (nuclear reactors). In addition to aeronautics, our company is able to provide maintenance, repair and training services to all organizations in all these sectors as well.

During the period of their utilization aircraft components are subjected to dynamic loads on the ground or the air and this causes some faults in time within these parts. It is obligatory for these faults to be determined at the initial phase and for the necessary procedures to be carried out. Non-Destructive Testing methods have a crucial importance at this point for the rapid and instant discovery of faults.  

As it is described in EASA PART 145.A.45 by manufacturers of aircraft, engine or propellers, Non-Destructive Testing in aviation is the whole of tests performed for the purpose of sustaining the conformance of the aircraft (airplane, helicopter etc.) or aircraft component in service. In addition to the surveillance of discontinuities occurring during service, it is possible to apply Non-Destructive Testing methods to aircraft and components which are manufactured in accordance with the technique of production.

The concept of discontinuity is in short, “An interruption occurring in the normal physical structure or configuration of a part”. Discontinuities encountered are defined as fatigue cracks, corrosion, creep and damages on composite structures. Non-Destructive Testing methods are decided according to the type of discontinuity investigated. For example, usually Liquid Penetrant Testing (PT), Magnetic Particle Testing (MT) and Eddy Current Testing (ET) are preferred for the investigation of fatigue discontinuities, whereas for the analysis of discontinuity entrapped within the structure volumetric methods such as Ultrasonic Testing (UT), X-Ray Radiography Testing (RT) and Thermography Testing (TT) are utilized. Non-Destructive Testing methods used in aviation and discontinuity types thereof are shown in Table 1 below.

Non-Destructive Testing Method Utilization Areas
Liquid Penetrant It is used for the detection of surfaced discontinuities in all metal and ceramic materials.
Magnetic Particle  It is used for the detection of surface and near surface discontinuities of ferromagnetic materials.
Eddy Current It is used for the detection of surface and near surface discontinuities of materials possessing electrical conductivity. Material’ electrical conductivity measurements are also in the scope of this method. 
Ultrasonic Surface and subsurface (volumetric) tests of materials are carried out.
X-Ray     Surface and subsurface (volumetric) tests of materials are carried out.
Thermography    Used for volumetric testing of honeycomb structures.
Non-Destructive Testing (NDT) is applied professionally in our maintenance/repair center
Non-Destructive Testing applications are being performed by the NDT Project Lead whose foundation dates back to the 1930’s as the first establishment that comes to mind in Turkey when it comes to aviation repairs and maintenance that is operating within Turkish Airlines Technic Inc. by using the latest technology products through a professional outlook.

Our department sustains its tests with six separate methods (PT, MT, ET, UT, TR, TT) on aircraft and on components with more than forty years of experience and experienced personnel. Aiming to constantly improve NDT methods, the unit has made an application to the General Directorate of Civil Aviation due to the placement of the Thermographic Test method into the classification of common methods within international standards in order to include tests it carried out with the authority of the manufacturing company earlier within its D1 Class Rating capability. Within this context, services are offered to respond to the requests and requirements of clients at standards set by national and international aviation authorities (SHGM, EASA, FAA) with experienced Level 2 and Level 3 NDT experts and engineering staff.

The NDT Project Management Unit of Turkish Airlines Technic Inc. that is a pioneer in Turkey in Non-Destructive Testing implementations signed service protocols with three universities in order to support the academic studies conducted in this area and to set up the Regional Non-Destructive Testing and Welding Education Centers. This protocol covers Non-Destructive Testing Methods (Liquid Penetrant Testing, Magnetic Particle Testing, Eddy Current Testing, Ultrasonic Testing and Radiography Testing) and welding engineering. The aim of the Protocol is to perform R&D work, cooperate in R&D projects to be conducted for the research and development of advanced materials that could be used in the aerospace industry.
We are Supplying Non-Destructive Testing Training at International Standards
As it is disclosed in the EN 4179 (Aerospace Series- Qualification and Approval Personnel for Nondestructive Testing) standard; Non-Destructive Testing activities are carried out by personnel that is properly qualified as Level 1, 2 and 3. EN 4179 sets out to contain the minimum requirements for the qualification and certification of personnel to carry out tasks in Non-Destructive Testing activities performed in aviation manufacturing, services and maintenance establishments.

NANDTB-TR was officially recognized with the publication of Civil Aviation Non-Destructive Testing Manual (CAI-NDT) published on 24.10.2011 by the General Directorate of Civil Aviation and the requirements for maintenance/repair companies and Approved Training Institutions active in the area of Non-Destructive Testing in the aviation sector were set out. In TURKISH TECHNIC, NDT Training activities are performed under by the ASNT NDT Level 3 with the authority of Approved Training Organization by NANDTB-TR.

NDT Project Lead is offering the training courses, qualified to the sector in the five methods listed below, by our professional instructors who have provided services in nearly 30 different training courses since 2009 to the present day and conducting the qualification of more than 200 personnel.

Level 1, Level 2 and Level 3 Trainings

1. Liquid Penetrant Testing (PT)
2. Magnetic Particle Testing (MT)
3. Eddy Current Testing (ET)
4. Ultrasonic Testing (UT)
5. Radiography Testing (RT)
Our Capabilities on a Type Basis in the Implementation And Training of Non-Destructive Testing
With more than one thousand reference standards and state-of-the-art testing instruments of the latest technology, we are in the position of leading implementer as in many other areas, in the area of Non-Destructive Testing, whose implementations are carried out by the NDT Project Management Unit operating in the organism of our affiliate Turkish Airlines Technic Inc.

Through the present D1 Class capabilities under our roof, tests are run on Boeing 737 Classic and 737NG, Boeing 777–200/300 ER, Airbus A320 Family, Airbus A300, Airbus A310, Airbus A330 and Airbus A340, BAE RJ - 70/85/100, GULFSTREAM G-IV, GULFSTREAM 550, CESSNA 172 and DIAMOND DA 42 aircrafts and their various components (engine, landing gear, wheel and brake systems, etc.). When requested, personnel assignment may be accomplished in a short time period for NDT applications everywhere in the world within the scope of authorities at hand (D1 Class Rating). Special applications highlighted in in-situ services are shown below;
  • UT Phased Array,
  • Thermographic Testing,
  • Barkhausen Noise Testing,
  • Eddy Current Testing of APS 3200 APU Components with Automated Robotic System
  • Ultrasonic and Eddy Current Testing on Aircraft Engines

UT Phased Array Testing is a special application emphasized in the discovery of corrosion that could possibly occur in aircraft wings. While the removal of actuators and panels in the area caused hundreds of M/H (man hour) before the development of this technique, the Phased Array technique moves the M/H periods in these location tests down to a minimum.

Thermography Testing
is becoming more important every day in parallel to the development in composite technology. It is a NDT method used for the detection of the water and moisture that is possible to be entrapped inside the composite structures, especially in the aircraft steering organs (Rudder, Elevator).

Barkhausen Noise Testing
is a special technique used in the detection of the heat damage occurring in the main material underneath the coated surfaces in aircraft landing gear, without stripping the coating on the area.

Aps 3200 APU Components Eddy Current Applications, the automatic Eddy Current Testing of rotating parts is done with the robotic system developed within the scope of the project.

Ultrasonic and Eddy Current Testings in Aircraft Engines,
in case it is requested for CFM–56 TRF and 3–8 Drum components it is possible to carry it out everywhere in the world.