The development and improvement of modern aircraft onboard radio-electronic equipment (avionics) is associated with the implementation of information and telecommunication technologies. As a result, the requirements for data transmission networks on aircraft are constantly growing. On the one hand, every year, the improvement of subscriber devices (traffic generators) of the aircraft on-board network requires increased performance of aircraft onboard information and telecommunication networks: greater throughput, scalability, ensuring the required level of delays. On the other hand, the execution of these requirements must be ensured with unconditional compliance with the mass-dimensional characteristics of avionics and the tendency to decrease them. As a rule, any technical decision taken in relation to aviation equipment (AE) proceeds from a compromise between the weight, size, and characteristics that the AE product must provide while considering the fact that the AE has strict requirements for resistance to external factors, reliability, and electromagnetic compatibility. According to the complexity of the testing cycle of single products and the increasing complexity of the task, problematic situations often arise during the development or modernization of systems, complexes, and sets of AE. In particular, the solution to the problem of ensuring the proper characteristics of on-board information and telecommunications networks is complex, but does not exclude the requirements imposed on the components of the whole system. In aviation, the object of electromagnetic compatibility (EMC) research is an aircraft and its onboard equipment capable of generating electromagnetic interference or being susceptible to it. A special research object is the external electromagnetic fields on the flight paths. The aircraft's onboard devices are divided into radio-electronic, electronic, and electromechanical; they are divided into potential sources and receptors of unintentional interference. The EMC of the aircraft's onboard equipment is determined by the characteristics of three main objects: sources of unintended interference, interference detectors, and the environment in which interference is propagated from the source to the receptor. Unintentional disturbances are considered sources of interference formed during the operation of aircraft onboard equipment and radiations of radio transmitting devices located outside the aircraft (land-based and sea-based and other aircraft). Onboard radio transmitters are the most powerful sources of unintentional interference on the aircraft. They emit continuous and pulsed signals in the frequency range from 2 MHz to 10 GHz. Their capacities are 20... 400 watts for continuous signals and up to several kW for pulsed. The spectrum consists of the main and extra-local radiation, radiation at harmonics of the operating frequency, noise and transit radiation. Potential sources of interference in the aircraft are pulse power converters, engine ignition systems, pulse de-icing systems, and digital electronic systems. The main parameters of the interference sources are the following: the interference power in the radio frequency (RF) range (f) and the width of the spectrum of generated interference ΔFgen(f). According to the degree of impact of failure on flight safety, aircraft systems are divided into four levels: A, B, C and D. Level A includes systems that perform so-called "critical" functions. Their violation leads to catastrophic consequences. Examples are telecommunications systems on board, electrical control, engine control, etc. Level B includes electrical and electronic systems that perform a function, the violation of which leads to an emergency situation. Level C includes electrical and electronic systems that perform functions, the violation of which significantly complicates flight conditions. Level D includes electrical and electronic systems that perform functions, the violation of which does not significantly complicate the conditions of the flight. Communication systems and aircraft navigation support systems are examples of level B and C systems, which are display systems that provide direction, location, and route data. Failure of a level B or C system is not catastrophic, but it can contribute to other failures. To date, the greatest danger is expected from the impact of pulsed radiation fields at frequencies from 400 MHz to 10 GHz, which mainly affect electronic circuits.