A Design Guide for Lightning Protection of Aircraft

Present understanding of aircraft lightning effects and the means that are available to protect against them has advanced to the point where it is possible to design an aircraft to be safe from hazardous lightning effects. Lightning protection is, of course, most effective, easiest to incorporate and least expensive when designed into an aircraft while it is still on the drawing board. Lightning protection can often be retrofitted onto existing aircraft, but the results are rarely as thorough, and the process is usually more costly. For most aircraft, adequate lightning protection influences the design of each of its major systems and structures. The designers of each system and structural element must be made aware of potential lightning problems and the resources that are available to help solve them. Many problems that have arisen in the past were due to lack of designer awareness rather than to inadequacies in available protection technology. Unfortunately, this technology is documented in numerous technical reports and references whose existence is unknown to many designers. Since space does not permit description of hardware protection methods in this paper, sets of checklists are provided for typical aircraft systems together with references to sources of further information. Hardware addressed in this paper includes externally mounted components, nonmetallic structures, fuel system hardware, and control surfaces. Examples of some of the more common problems are also given.