Applications of NDT in Aerospace Industry

Non Destructive Testing Applications in Aerospace

Non-Destructive Testing occupied very important role in recent times in industrial applications like Aerospace, aircraft overhaul, automotive, petrochemical and gas, railway, mining, agriculture, power generation, iron, shipbuilding, steel, pipe and tube manufacturing industries etc as a powerful quality tool. Mainly in Aerospace industry in view of high quality requirements safety and stringent Airworthiness requirements. All components are inspected before they are assembled into the aircraft and then they are periodically inspected throughout their useful life.

Most of the inspections done to an aircraft are visual inspections. During heavy maintenance work, much of the interior of the aircraft is stripped out so inspectors can look for damage on the inside surface of the fuselage. Aircraft suffer many types of structural deterioration including corrosion, fatigue, fabrication defects, operation and maintenance, and unforeseen loading. In aircraft maintenance, it is critical to inspect surfaces for any damage that may exist in order to determine the extent of repair work needed, whether that occurs as the result of manufacturing or while the aircraft is in service.


Non-destructive testing (NDT) is one of the quick and most economical ways to perform inspections in Scheduled maintenance and the only way to discover defects that are not visible to the naked eye.

NDT Methods Used in the Aerospace Industry
Several types of non destructive testing methods like liquid penetrant testing, ultrasonic testing, magnetic particle testing and eddy current testing are used to test airplanes.

Liquid Penetrant Testing (LPT)
To reveal the cracks on the surface of airplane, Liquid penetrant testing is one of the most commonly used method in NDT in aerospace industry.

“The fundamental purpose of penetrant testing is to increase the visible contrast between a discontinuity and its background,” said a report on NDT techniques used in the aerospace industry.
Structural damages or surface defects of aircraft materials were observed with LPT. Fluorescent penetrants are used in critical areas for more sensitive evaluation.
Ultrasonic Testing (UT)
The most common sub-surface inspection technique, ultrasonic NDT uses high-frequency sound waves to locate defects under the surface.UT has many uses in the aerospace industry including detection of:

Surface and subsurface defects in welds;
Main structural fittings of landing gear legs and engine attachments;
Aircraft structure joints and pylons;
Bolts located in critical areas;
Adhesive bond quality of lap joints and composite structure;
Thickness measurement after damage or corrosion removal.


Magnetic Particle Testing (MPT)
In magnetic particle testing, fine particles are applied to the surface to monitor magnetic flux. If damage exists, flux “leaks” from the item’s surface, attracting particles to the area.
In the aircraft, MPT is conducted on engines, pumps, landing gear, gearboxes, shafts, and shock struts. It is also widely used for bolt inspection.
Obviously, this task requires trained professionals who are capable of performing a variety of different NDT techniques to get a complete and accurate status of the airplane.
Eddy current Testing (ECT)
In any aerospace maintenance and repair organization Eddy current testing plays an important role.

Eddy current testing is used in Surface Crack Detection on Aluminum alloys
Intersect the inner surface of holes in the component to be inspected.
Automated Inspection of Aircraft Wheels / Wheel Hub / Rotor Disc
Subsurface Corrosion Detection
There is no question that the success of the airplane industry is dependent on NDT. Without NDT, the cost of maintaining and flying in airplanes would increase dramatically, while the safety of flying would decrease. When people step into an airplane they trust that it will get them to their destination with as little turbulence as possible. NDT plays a vital role in keeping air travel one of the safest modes of transportation.