Lightning Requirements: Where They Come From and How to Analyze Their Impact

Many avionics and aircraft equipment manufacturers use DO-160 [Ref. 1] Section 22 to test their equipment for indirect effects of lightning without understanding why they are testing to specific values. Many aircraft manufacturers struggle with determining the level of indirect lightning that will be acceptable for their vehicle and what level of requirements they need to pass down to the avionics and aircraft equipment manufacturers. Organizations like SAE and RTCA, Inc. work to collect data on lightning and spend countless hours assimilating the information and developing documents to help engineers use the information. They struggle with knowing what data is pertinent and how it will be received and used by the engineering community. This paper walks through the process of how the lightning levels are developed, how the levels get selected for a particular application, and how to use this information to perform an analysis of the survivability of a specific circuit in an electronic system. This paper will provide an introduction of the process that each of the three primary levels of experts use to contribute to the overall design of flight hardware that is safe to fly in a lightning environment. The purpose of this paper is to provide information to all three levels of experts about how their data is being used and what information is useful for carrying on the design process.