This user’s manual provides detailed information, guidance and methods in support of the Federal Aviation Administration (FAA) Advisory Circular (AC) 20-136 entitled Aircraft Electrical and Electronic System Lightning Protection. This AC provides a means, but not the only means, for demonstrating compliance with Title 14 of the Code of Federal Regulations (14 CFR) 23.1306 (up to amendment 63), 23.2515 (amendment 64 and up), 25.1316, 27.1316 and 29.1316, Electrical and Electronic System Lightning Protection. It is also intended for this guide to provide the same information, guidance and methods, to the European Aviation Safety Agency (EASA) Lightning Indirect Effects certification requirements and associated Acceptable Means of Compliance AMC 20-136 entitled Aircraft Electrical and Electronic System Lightning Protection. This guide provides references relevant to identifying: (1) acceptance criteria for the indirect effects of lightning compliance approaches, (2) verification (analysis and test) methods including those associated with multiple stroke and multiple burst, (3) recommended design options to optimize needed system immunity to lightning indirect effects and (4) provide guidance in the areas of continued airworthiness of the lightning protection. Equipment hazards due to the indirect effects on equipment mounted on the aircraft exterior, equipment located within the aircraft interior as well as all associated interconnecting wiring are addressed. This document provides additional guidelines in the application of indirect effects of lightning tests identified in DO-160/ED-14, Section 22.