Aviation Mechanic - General, Airframe, and Powerplant › II. Airframe › Task B. Non-Metallic Structures

AM.II.B.K19

Knowledge

Types of composite structure defects.

Study note

Get a short, cited explanation of this element written from the FAA handbooks: the core idea, the numbers that matter, common test traps, and a quick self-check.

From the FAA library

Aviation Maintenance Technician Handbook - General p. 10-36
Chapter 10: Inspection Concepts & Techniques › Inspection of Composites › Tap Testing
defects in relatively thin skins, less than 0.080" thick. On honeycomb structures, both sides need to be tested. Tap testing on one side alone would not detect debonding on the opposite side. [Figure 10-37] Electrical Conductivity Composite structures ... inherently electrically conductive. Some aircraft, because of their relatively low speed and type of use, are not affected by electrical issues. Manufacturers of other aircraft, such as high-speed, high-performance jets, are required to utilize various methods of incorporating…
Aviation Maintenance Technician Handbook - Airframe p. 7-15
Chapter 7: Advanced Composite Materials › Nondestructive Inspection (NDI) of Composites › Audible Sonic Testing (Coin Tapping)
Visual inspection cannot find internal flaws in the composite, such as delaminations, disbonds, and matrix crazing. More sophisticated NDI techniques are needed to detect these types of defects. Figure 7-23. Corrosion of aluminum lightning protection mesh. Audible Sonic Testing ... inspection area with a solid round disc or lightweight hammer-like device and listening to the response of the structure to the hammer. [Figure 7-24] A clear, sharp, ringing sound is indicative of a well-bonded solid structure, while…
Aviation Maintenance Technician Handbook - Airframe p. 7-13
Chapter 7: Advanced Composite Materials › Manufacturing Defects › Delamination & Debonds
Delamination & Debonds Delaminations form on the interface between the layers in the…