The subject of avionics systems of both fighter aircraft and civil aircraft. Modern integrated avionics systems implement various complex functionalities of the aircraft. and have interfaces with all the other systems on board the aircraft. This makes the design and development of avionics systems a complex process. This monograph covers all these aspects in detail. Subjects covered include: Avionics System Functionalities, Subsystems, System Design, Speciality Engineering topics like QA, Reliability and EMI/EMC, Development, Safety, Integration, Testing and Certification of Avionics Systems. It also covers lessons learnt in most of the topics based on the experience of the author in the Indian Light Combat Aircraft (LCA)-Tejas Program. Design for Safety which requires adoption of Fault Tolerant features–both in hardware and software, modern software engineering processes and tools are also dealt in detail. Pilot Vehicle Interface (PVI) and Human Factors (HF) are important topics covered as part of the cockpit design, automation and safety design. Certification aspects for both fighter and civil aircrafts are covered. Multi Mode Radar (including AESA), EW systems and EM and IR sensors including reconnaissance pods are covered. Modern techniques and future trends in avionics are also elaborated. This book will be of interest to avionics engineers, technicians, operators, maintenance engineers and all those who have interest in avionics systems.