In the past, civil aircraft were assessed for electromagnetic compatibility in terms of the ability of onboard systems to coexist without incompatibility problems. However with the advent of electronic into safety critical systems on a new generation of civil aircraft, the aviation authorities became concerned about the potential interference effects of High Interference Radiated Fields (HIRF). The HIRF is generated by emission groups located in aircrafts, airports, ship/boat, such as antennas, radar, navigation/communications instruments, transmitters, among others. The results of interaction of the external electromagnetic fields with aircraft structure and electric-electronic systems herein installed can be generate a high intensity of voltage and current transients, occasioning hazard to electronic equipments and operational reliability. Actually, the necessity in the analysis of HIRF effects in aircrafts are related, principally, to increase of composite materials employed in structural parts of aircraft (promote reduction of HIRF protection) and large quantity of electric-electronics equipments utilized (increase of susceptibility on electromagnetic fields). Therefore, the purpose of this work is study and analyze the HIRF effects in aircrafts and, consequently, possible HIRF protections employed.