FAA Powerplant Written Practice Test

If delamination is suspected on a composite propeller, how can the extent of damage be confirmed?

1. By visual inspection

2. By ultrasonic inspection

3. By magnetic particle inspection

4. By dye penetration test

The correct answer is: By ultrasonic inspection

Ultrasonic inspection is a highly effective non-destructive testing technique that uses high-frequency sound waves to identify internal flaws or irregularities in materials, including composite propellers. When delamination is suspected, ultrasound can penetrate the composite structure, providing data on the thickness of the material and revealing any areas where layers may have separated. This method offers several advantages: it can assess the size and location of the delamination, is capable of detecting layers that may not be visible to the naked eye, and can evaluate internal defects without damaging the propeller. The use of ultrasonic inspection in this context is standard practice in aircraft maintenance and repair, ensuring that any potential issues are identified and addressed before they affect the safety and performance of the aircraft. Visual inspection may not adequately reveal the extent of internal damage, particularly for defects not visible on the surface. Magnetic particle inspection is primarily used for ferromagnetic materials, which do not apply to composite propellers. The dye penetration test is intended for surface defects and would be ineffective in detecting layers that have delaminated within the composite material. Thus, ultrasonic inspection stands out as the appropriate method to confirm the extent of damage in this scenario.