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Electrical characteristics of composite Wiring Integrated Assembly (WIA) chassis’s when subjected to lightning environment are studied. The wiring architecture of the Bell Agusta Tiltrotor civil aircraft designated as Model BA609 includes WIAs that are shielded junction boxes. The WIAs are required to maintain wire bundle shield continuity to ground when exposed to the effects of a lightning event. Test results demonstrate that the composite WIAs having copper and nickel plating can withstand lightning currents up to 20 KA. A description of the WIAs, as well as lightning test procedure and results using waveforms 5A and 5B are presented.

Under Contract No. N00019-93-C-0006 EMD with the Department of the Navy, Bell Helicopter Textron Inc. (BHTI) conducted a Manufacturing Process Verification Test as part of the V-22 Engineering Manufacturing Development process. The objective of this test was to develop a “One Step” drilling solution for peck drilling close tolerance holes in V-22 major assemblies. These assemblies consist of Titanium / Graphite / Titanium and Aluminum / Graphite compositions. The V-22 is a graphite / epoxy composite structure that has metal detail parts mechanically attached to the basic structure. Attachment of these detail parts is accomplished with two piece titanium fasteners that require a close tolerance of .003″ per hole. To achieve this tolerance a drill / ream process is currently used.

Design limits in aerospace are constantly being challenged forcing engineers to look for materials and material combinations that will provide the strength needed, yet meet the lightweight requirements demanded throughout the industry. These material combinations provide demanding and unique challenges to all involved in the development of robust, reliable assembly processes. As advancements are pushed forward in aircraft materials, advancements must also be made in the technologies/methodologies used to drill close tolerance holes in these complex materials. These advancements will be discussed in the following paper. Common stack-ups of aircraft materials include various combinations of graphite, aluminum, and titanium. Many problems arise when trying to drill the different combinations of these materials due to the extreme differences in physical properties.