The science of electronics that are being in producing or making, as well as, designing the aircraft is basically called as avionic. Aside from aircraft, the term avionics is also referring to the electronic systems that can be used on spacecraft and artificial satellites. The electronic systems that are being used in avionics are typically called as avionic system, and examples of these essential systems include the management and display of multiple systems, communications, fuel systems, weather systems, flight recorders, aircraft flight-control system, navigation, collision-avoidance system, and some other systems with specific functions and are mostly being fitted on the aircraft. The term avionics is actually a combination of two other terms, and just to state the obvious, those two terms are aviation and electronics. You can see here for more details.
In order to produce and develop an aircraft successfully, especially its electronic hardware, most of the manufacturers and technicians are using a specific document that will guide them throughout the process. This particular document is called as the Design Assurance Guidance for Airborne Electronic Hardware, and can also be shortened as DO-254. The said document basically provides the user with guides as they develop and install the various airborne electronic hardware on the aircraft. It is also recognized as compliance for the design assurance of the various electronic hardware that is specifically designed in airborne systems. Some of the most common electronic hardware that is being used for airborne or aviation systems include the COTS components which stand for commercial off-the-shelf components, integrated technology components, line replaceable units, circuit board assemblies, and various custom micro-coded components. Some of the most common items that are considered as custom micro-coded components include the ASIC which stands for application-specific integrated circuits, the FPGA which stands for field-programmable gate arrays, and the PLD which stands for programmable logic devices. Some of the processes that are included in the said document are the application to any simple electronic hardware, some of the essential or important considerations, the planning process, the hardware design life cycle, some additional considerations, as well as, the processes for validation and verification. Due to the importance of this particular document in the aviation industry, there are actually a lot of providers that can be found on the internet. The said document may be downloaded for free on their very own devices, and the best way for this is to find the right and legit online provider of the DO-254. You can learn more in this site: https://www.britannica.com/technology/aerospace-industry/Helicopters.