This document is one of a set covering the whole spectrum of aircraft interaction with lightning. This document is intended to describe how to conduct lightning direct effects tests and indirect system upset effects tests. Indirect effects upset and damage tolerance tests for individual equipment items are addressed in DO-160/ED-14. Documents relating to other aspects of the certification process, including definition of the lightning environment, zoning, and indirect effects certification are listed in Section 2. This document presents test techniques for simulated lightning testing of aircraft and the associated systems. This document does not include design criteria nor does it specify which items should or should not be tested. Acceptable levels of damage and/or pass/fail criteria for the qualification tests must be approved by the cognizant certification authority for each particular case. When lightning tests are a part of a certification plan, the test methods described herein are an acceptable means, but not the only means, of meeting the test requirements of the certification plan. Each test method is set out in a uniform format, describing the test purpose, test object, test setup, test waveforms (voltage and/or current), measurements and data recording, test procedure and data interpretation. Guidance is provided on how to select the appropriate test or series of tests, and how the test results can be assessed. Natural lightning is a complex and variable phenomenon and its interaction with different types of vehicles may be manifested in many different ways. It is not intended that every test described herein be applied to every system requiring lightning verification tests. The document is written so that specific aspects of the environment can be called out for each specific program as dictated by the vehicle design, performance and mission constraints. With the original release of the document, many new test methods were provided to account for aircraft operational experience and changing aircraft technology, including more reliance on electronic data and control systems and increasing use of composite materials in aircraft structures. As experience is gained with these test methods, some changes and clarifications are needed to ensure consistency across test organizations, particularly regarding high voltage tests and integrated system functional upset tests. Also, ignition source detection methods have historically relied upon the use of Polaroid film as the standard. Since this film’s source of supply is rapidly disappearing, photographic methods using modern camera technologies needs to be included in the recommended practice.