Nondestructive Research In Service

The global market and international competition are urging aircraft operators to continuously enhance their performance in the operational process. Operators have to find the right balance between reducing maintenance costs while increasing the fleet availability and ensuring safety. The application of novel Non-Destructive Inspection (NDI) methods and availability of more accurate operational information is of key importance for the further reduction of aircraft downtime and direct maintenance costs, the predictability of aircraft availability, and the everlasting need to improve the price-performance ratio of aircraft operations and maintenance. The goal of this innovation track is to develop a reliable, fast and automated non-destructive inspection method for large surfaces of composite material.

Innovation Track 2: Developing a scanning method for large surfaces

Composite material requires a very different method of NDT inspection than other materials used in the aviation sector, such as  aluminium. Experiences have shown that a single NDT technique is insufficient to obtain a reliable picture of the condition of the composite material. Suspicious indications according to one technique must be checked with another technique to obtain 100% certainty and to prevent unnecessary repairs. Because damage is often not visible on the outside, the surfaces must be fully inspected. Conducting manual research on these large and often hard-to-reach surfaces is very time-consuming and poorly reproducible.

Optical techniques

Due to the fact that most non-destructive methods are complementary to each other, a multi-domain inspection tool is developed as part of this innovation track to detect the most common defect types in composite structures. The following optical techniques are selected to provide the complete technical status of the composite component in one inspection step:

  • 3D structural light scanning to determine possible surface damage due to foreign object damage (FOD)
  • Active thermography for “in-depth” damage
  • Laser shearography for de-bonded sandwich constructions

3D surface mesh

The NDI methods are evaluated on composite reference samples with controlled representative natural or artificial defects. The 3D structural light data generates an accurate 3D surface mesh. The thermography and shearography data are then automatically mapped on the 3D surface. The developed multi-domain unit is capable of inspecting 1m2 within a few minutes in a non-contact manner. All information, such as position and size of defects, can be input for a digital twin or for e.g. a robot for repair.

The innovation in this track is symbolised by combining the different non-destructive testing techniques plus the data sampling of the results to paint one reliable overall picture. A component of this track is performing a non-destructive scan by a robot to ensure high accuracy.

Picture: TiaT

Project status

Runtime: January 2018 – end of March 2023

NLR’s activity is developing new NDI techniques to let the operators perform inspection in a more efficient and accurate way.

TiaT’s activities are mainly focused on the operational non-destructive evaluation (empirical research) and the University of Delft concentrates more on experimental and scientific research. So empirical results can be scientifically underpinned.

Project closed.


NLR-CR-2019-100-RevEd-1 Evaluation of in-service active thermography for composite structures

NLR-CR-2019-513-RevEd-1 Round Robin Test Results of Laser Ultrasonic Systems on Composite Panels 

NLR-CR-2018-365-RevEd-1 Evaluation on in-service laser shearography for composite structures

Parties involved

More information

For any questions about the project (status) or if interested to collaborate, please contact: Jacco Platenkamp at 
or Pieter Troost (TiaT) at