Improved Aircraft Inspection – JET CHECK
      Increase Safety and Your Bottom Line with Our Turn-Key Solution

“The increasing number of air travelers combined with a greater number of aging commercial jetliners has led to more stringent inspection and maintenance procedures. Inspection methods that can detect minute defects that could lead to catastrophic failure are required to keep air travel safe.”
- Markus Tarin, President of moviMED

After official approval by the Federal Aviation Administration, lock-in thermography is now being used in both the USA and abroad by companies such as Lufthansa Technik to perform aircraft fuselage inspection. MoviMed is pleased to offer this cutting edge inspection method to American companies.

The time consuming inspections required by the FAA are a continual challenge to airlines who must balance the need to have their aircraft operational to meet flight schedules and the significant down-time required for the lengthy inspections.

This problem has most recently been highlighted in the news when Southwest Airlines was charged by the FAA for neglecting it's hull inspections. Because Southwest allegedly operated 46 airplanes without conducting mandatory checks for fuselage cracking, they could be looking a several areas of loss: 1) Credibility with the public, 2) A possible $10.2 million civil penalty and, 3) Costly downtime for the fleet; 44 planes in all were grounded for re-inspection. According to the FAA, the airline later found that six of the 46 planes had fatigue cracks (source: CNN).

Not only does JET-CHECK improve airline inspection methods, it significantly increases the bottom-line for the airline companies because using JET-CHECK increases efficiency by 10X.

Jet-Check uses the Measuring Principle of "Thermal Radioscopy"

Thermal stimulation with a modulated heat source

Measurement of the thermal response as a function of time with an infrared camera

Signal analysis

The Jet-Check system allows rapid inspection of the fuselage and other structural components of any aircraft, allowing quick location of micro-fractures, cracks, impact damages, delaminations, loose rivets and water inclusions. Inspect large areas of the aircraft for material fatigue problems to avoid catastrophic failures.

Jet-Check uses a variant of IR thermography known as “lock-in” thermography to analyze samples under test. In this method, the sample to be tested is heated at its surface by an intensity modulated source. This heat penetrates into the interior of the sample as a thermal wave and any change in the properties of the sample material such as cracks, cause a change in the propagation characteristics of the wave.

After the thermal wave is reflected to the surface of the sample, it becomes superimposed (or “locked-in”) onto the initial wave such that any defect is revealed by a local change in the phase angle. By recording the surface temperature of the sample with an IR camera, the temperature-time function of the image can be analyzed on a host computer. By calculating a phase image, the internal structure of the component and its interior defects are revealed. Depending on the modulation parameters of the heat source during the measurement, different depth ranges within the image can be displayed.

Aircraft hulls are manufactured using a variety of different materials and fasteners such as aluminum and rivets, carbon fiber reinforced plastics (CFRP), honeycomb structures and other composite materials. Due to constant temperature changes, pressurization and depressurization, vibration and high wind loads, material fatigue occurs. This can cause de-rivetting, impact damages, cracking and hull de-lamination. Other factors such as condensate and water inclusion can also cause cracks at high altitudes.

Infrared image of 737 hull                 Resulting image shows disbondings clearly identified

To inspect for these types of defects, the Jet-Check system can be used to inspect several square meters of an aircraft within minutes. To do so, the exterior is heated to no higher than 40oC using an array of high-power halogen lights so not to cause damage or deformation to the fuselage. The halogen lamp array is modulated using a sinusoidal waveform. Instead of directly measuring the temperature of the object, the system measures and evaluates differences in the temporal behavior of the heat at the object surface and defects appear with excellent contrast. The advantage of using lock-in thermography with phase angle image evaluation is that external effects, such as emissivity of the material and other radiation effects such as sunlight do not affect the results of the measurements.

In the Jet-Check system, thermal images are captured by a ThermoVision cooled focal plane array (FPA) IR-camera from FLIR Systems, Inc. Using an 640 x 512 InSb focal plane array (FPA), the camera transfers 120 fps, 14-bit digital images to a PCI-based proprietary frame grabber board resident in a host PC running Windows XP. The frame grabber also contains the circuitry for generating the sinusoidal stimulus signal to the halogen lamp array and performs the synchronized IR-image recording. IR NDT proprietary application software running on the PC allows for test setup and phase and amplitude thermal image analysis. As well as controlling the heat source and IR camera, the software is used to store both live images from the camera in real-time and calculate the phase image from the IR data.

Jet-Check Features

Measurement speed:

• Depending on the measurement object, ≤ 2 minutes for large scale measurement of the hull of an aircraft.

Heating of measurement object:

• Defects like delaminations, cracks, loose rivets or water inclusions. Suitable for different materials and material combinations e.g. aluminum, carbon- or glassfiber reinforced plastics and honeycomb structures.
• During the measurement the component is warmed up to a short time maximum temperature of less than 40C. Damages or changes of the shape are impossible.
  

Ease of Use:

• The system allows a manual as well as an automated inspection process.
• Instead of temperatures the system measures and evaluates differences in the temporal behavior of the heat at the object surface. Therefore the system shows defects with an excellent contrast.
• Measurement results are clearly reproducible and are insensitive to any external effects.