This text details the operation of predominantly electrical and electronic (avionics) aircraft systems, as well as their standard maintenance methods. As a result, it is an especially practical work for aspiring Aeromechanical Maintenance Technicians, who must master the included contents to perform their job properly and achieve professional growth. The work is fully adapted to the contents of Module 11A (Turbine Aeroplane Aerodynamics, Structures and Systems) of Part 66 of Regulation (EC) 1321/2014, making it ideal for obtaining the EASA AML B1.1 Aircraft Maintenance Licence (Turbine Engine Aeroplane), as it covers each section with the appropriate depth. Furthermore, the text includes numerous and varied self-assessment questions at the end of each unit, alongside a bank of 640 multiple-choice questions highly similar to those that candidates will encounter in the official licence exam. It is worth noting that this book fully aligns with the Aerodynamics, structures and electrical and avionics systems of turbine engine aeroplanes module, belonging to the Higher Vocational Training Course in Turbine Engine Aeroplane Aeromechanical Maintenance. Additionally, its content is comprehensive enough to be highly useful for studying the electrical and avionics systems of helicopters and piston engine aeroplanes. Finally, the work is fully illustrated with figures, images, and diagrams that facilitate the comprehension of the content and serve as valuable support for obtaining the Aircraft Maintenance Licence. The author, an aeronautical engineer from the Universidad Politécnica de Madrid, has over fifteen years of experience training aeromechanical maintenance technicians. He has also published with this publishing house the books Module 1 (Mathematics), Module 2 (Physics), Module 3 (Electrical Fundamentals), Module 4 (Electronic Fundamentals), Module 5 (Digital Techniques. Electronic Instrument Systems), and Module 17 (Propellers).