Electromagnetic compatibility (EMC) is a very important and increasingly relevant technology in use and is closely related to many technologies such as automobiles and aerospace industry technology including aircraft and spacecraft. Achieving electromagnetic compatibility between equipment inside the device is more than necessary to avoid the problem of interference leading to serious problems. More than that, achieving electromagnetic compatibility for the device as a complete system is quite challenging. The device as a whole system is necessary to be compatible with its electromagnetic environment in order to avoid the problem of interference with other devices which also leads to safety issues. The objective of the thesis is to measure EMC radiated emission from the aircraft as a complete system and to know its compatibility with its electromagnetic environment, by building knowledge of the challenges that arise when conducting electromagnetic compatibility measurements of the aircraft as a whole system outside a protected environment. The challenge here is that there are no standards for EMC radiated emission of the aircraft as a complete system in an Open Area Test Site (OATS). This required us to research and try to relate what was done in this field to try to plan to build an OATS to conduct EMC radiated emission on aircraft as a whole system. We have come up with, that the measurement of EMC radiated emissions performed on the aircraft as a complete system in an OATS at Skellefteå Airport, shows similar results to those obtained on Aircraft SIMulator (ASIM) tested in a Fully Anechoic Chamber (FAC). In addition, we performed a civil airport of Skellefteå site validation measurement and obtained the result that the site complies with the OATS requirements in CISPR 16-1-4: 2019 standard. This work is considered a building block for other EMC studies in the field of space technology, which calls for the need to think about achieving electromagnetic compatibility to avoid all that results from electromagnetic interference (EMI) on the safety of pilots, astronauts, and all human life.