This work delivers the essential principles and knowledge base required by Airframe and Propulsion (A&P) Mechanics for Module 5/11 and 13 of the EASA Part-66 syllabus and BTEC National awards in aerospace engineering. It is comprehensive and accessible, with self-test questions, exercises and multiple choice questions to enhance learning for both independent and tutor-assisted study. It is accompanied by a fully worked Instructor's solutions manual and an online image bank for use in lecture presentations and in teaching materials. This book introduces the principles of communications and navigation systems. Written for anyone pursuing a career in aircraft maintenance engineering or a related aerospace engineering discipline, in particular it will be suitable for those studying for licensed aircraft maintenance engineer status as part of an EASA or FAR-147 approved course or taking Aerospace Engineering City and Guilds modules, EDEXCEL National Units, EDEXCEL Higher National Units or a Degree in aircraft engineering.