PDF Publication Title:
Text from PDF Page: 226
9/8/98 AC 43.13-1B e. In-Service Flaws. These flaws are formed after all fabrication has been completed and the aircraft, engine, or related component has gone into service. These flaws are attrib- utable to aging effects caused by either time, flight cycles, service operating conditions, or combinations of these effects. The following are brief descriptions of some in-service flaws. (1) Stress corrosion cracks can develop on the surface of parts that are under tension stress in service and are also exposed to a cor- rosive environment, such as the inside of wing skins, sump areas, and areas between two metal parts of faying surfaces. (2) Overstress cracks can occur when a part is stressed beyond the level for which it was designed. Such overstressing can occur as the result of a hard landing, turbulence, acci- dent, or related damage due to some unusual or emergency condition not anticipated by the de- signer, or because of the failure of some re- lated structural member. (3) Fatigue cracks can occur in parts that have been subjected to repeated or changing loads while in service, such as riv- eted lap joints in aircraft fuselages. The crack usually starts at a highly-stressed area and propagates through the section until failure oc- curs. A fatigue crack will start more readily where the design or surface condition provides a point of stress concentration. Common stress concentration points are: fillets; sharp radii; or poor surface finish, seams, or grinding cracks. (4) Unbonds, or disbonds, are flaws where adhesive attaches to only one surface in an adhesive-bonded assembly. They can be the result of crushed, broken, or corroded cores in adhesive-bonded structures. Areas of unbonds have no strength and place additional stress on the surrounding areas making failure more likely. (5) Delamination is the term used to de- fine the separation of composite material lay- ers within a monolithic structure. Ultrasonic is the primary method used for the detection of delamination in composite structures. 5-6. SELECTING THE NDI METHOD. The NDI method and procedure to be used for any specific part or component will generally be specified in the aircraft or component manufacturer’s maintenance or overhaul manuals, SSID’s, SB’s, or in AD’s. NOTE: Some AD’s refer to SB’s which may, in turn, refer to manufac- turer’s overhaul or maintenance manuals. a. Appropriate Method. The appropriate NDI method may consist of several separate inspections. An initial inspection may indicate the presence of a possible flaw, but other in- spections may be required to confirm the original indication. Making the correct NDI method selection requires an understanding of the basic principles, limitations, and advan- tages and disadvantages of the available NDI methods and an understanding of their com- parative effectiveness and cost. b. Other Factors. Other factors affecting the inspection are: (1) The critical nature of the component; (2) The material, size, shape, and weight of the part; (3) The type of defect sought; (4) Maximum acceptable defect limits in size and distribution; (5) Possible locations and orientations of defects; Par 5-5 Page 5-5PDF Image | AFS-640
PDF Search Title:
AFS-640Original File Name Searched:
ac_43.13-1b_w-chg1.pdfDIY PDF Search: Google It | Yahoo | Bing
5,000 BF Shipping Container Lumber Dry Kiln For Quality Lumber The 5,000 BF container kiln consists of one 40 foot high-cube aluminum shipping container... More Info
Shipping Container Lumber Dry Kilns by Global Energy Global Energy designed and developed the container kiln back in 1991. The purpose is to give access to portable sawmill owners, furniture makers, and small business the value added profit of dry kiln lumber and quality hardwoods... More Info
Vacuum Kiln Conversion Kit for Lumber and Wood Dry Kilns Convert your existing conventional dry kiln into a fast drying vacuum kiln. Similar to vacuum bagging in the boat building and aircraft industry, we have come up with a proprietary process which allows you to build a very simple vacuum kiln at a fraction of the price, and without the intensive conventional metal chamber structure... More Info
Vacuum Pump Cart System for Bagging Clamping Wood Drying and more Vacuum Cart with 2HP Pump and Dual Pistons with multiple multiplex vacuum ports and liquid reservoir... More Info
Vacuum Bagging Basics Vacuum bagging is a method of clamping, which has traditionally been used in the composites industry, but can also be used for vacuum drying materials, including wood products... More Info
CONTACT TEL: 608-238-6001 Email: greg@globalmicroturbine.com (Standard Web Page)