Introducing the principles of communications and navigation systems, this book is written for anyone pursuing a career in aircraft maintenance engineering or a related aerospace engineering discipline, and in particular will be suitable for those studying for licensed aircraft maintenance engineer status. It systematically addresses the relevant sections (Air Transport Association of America chapters 23/34) of modules 11 and 13 of part-66 of the European Aviation Safety Agency (EASA) syllabus and is ideal for anyone studying as part of an EASA and FAR-147-approved course in aerospace engineering.