The aerospace industry uses a wide variety of testing methods to ensure the safety of all aircraft systems and parts. The most effective of which is Ultrasonic Testing (UT) which utilizes a series of high-frequency ultrasonic waves to identify flaws in materials. This testing method is both highly accurate and completely non-destructive meaning that systems and components do not need to be destroyed in order to the gather information that is being sought. There are several different types of ultrasonic testing, including:
- Automated Ultrasonic Backscatter Technique: This UT technique has been developed for detecting damage from High-Temperature Hydrogen Attack (HTHA). High frequency waves are used with this technique in conjunction with as a digital oscilloscope. It is most often used in pressure vessels and piping.
- Dry-Coupled Ultrasonic Testing: This technique of UT is a low-cost method that does not require a liquid constant to be present in order to inspect metallic and nonmetallic material. Additionally, Dry-Coupled Ultrasonic Testing (DCUT) can be performed using remote transducers. The advantage of remote transducers is that they can take thickness measurements at non-conventional angles.
- Time of Flight Diffraction (TOFD): This method is commonly used to detect flaws in welds. Thus, it is useful in the aerospace industry as well as other fields to detect structural anomalies. It uses the time of flight of an ultrasonic pulse to find the location of a reflector. With this technique, low frequency waves are used and diffract back to the receiver only if a flaw is detected.
- Internal Rotating Inspection Systems: This technique is used to detect and size corrosion in piping and tubing. It was first devoted in the 1970s and was first used in 1978. It works by inserting and a probe through a piece of equipment. From there an ultrasonic beam is radiated towards the internal tube wall. In short, this method detects flaws both on the inside and outside of tube walls.
The primary advantages and disadvantages when compared to other NDT methods are:
- It provides instantaneous results.
- Detailed images can be produced with automated systems.
- It is nonhazardous to operators or nearby personnel and does not affect the material being tested.
- It has other uses, such as thickness measurement, in addition to flaw detection.
- Its equipment can be highly portable or highly automated
- Skill and training is more extensive than with some other methods.
- It normally requires a coupling medium to promote the transfer of sound energy into the test specimen
- Reference standards are required for both equipment calibration and the characterization of flaws.
In short, no inspection method is without its limitations. However, ultrasonic testing is a superior method with a great amount of versatility in its applications. In fact, this is why many aeromechanics specialists have access to one ultrasonic inspection system or another. We can provide you with one of our ultrasonic tower systems as well as other systems that will gauge the airworthiness of your fleet without making your suffer from unreasonable (and unprofitable) downtimes.