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The electro-electronic equipments of the aircraft are involved by electromagnetic fields which are inherent to the normal operation of installed equipment/systems, like radar and transmitters or hydraulic and fuel pumps. There are several systems and equipment that are inherently emissive, like VHP transmitters and weather radar, and there are several other that are inherently or by design potentially sensitive to a wide range of frequencies. Overall electromagnetic compatibility of operation must be achieved for all equipment installed in the aircraft and this concern is first applicable in terms of simultaneous operation of the aircraft installed equipment. The objective of this work is present and discusses the EMI effects and, subsequent, possible EMI protection employed in aircrafts, establishing minimal control of all of these effects with no hazard to flight safety and operational reliability.

The imprecision of altimeter system in higher altitudes, utilized by aircrafts in past decades, although adequate for lower levels, imposed that minimum separation between flights levels FL290 (29000 feet) and above had to be 2000 feet. This higher separation limits aircraft capacity on these levels where jets are more efficient and, therefore, is undesirable to airline companies, taking account, principally, the fuel economy. The advance of electronic technology in altimetry system has permitted to obtain a better precision of altitude measurements and, thus, reducing the minimum vertical separation between these levels to 1000 feet became safer, showed by figure 1. This process is called RVSM (reduced vertical separation minimum) and presents some characteristics such as introduction of 6 news flight levels. This process defines special requirements related to airspace and it was implemented in North America and Europe in last years.

In a wide variety of applications, mechanical components have to operate under severe conditions, such as high load, speed or temperature and hostile chemical environment. Thus, ceramic coatings produced by thermal etching techniques are widely used for a range of industrial applications, to confer wear and erosion resistance, corrosion protection and thermal insulation. Thus, this work has as objective to deposition of the alumina ceramic powder by plasma etching in the combustion engine components (piston, valves, combustion camera), actuating such as thermal insulation to increase temperature in the combustion camera and consequently improvement of the efficiency and power. The ceramic-metal adhesion, thermal/mechanical and thermal insulation properties were evaluated by SEM and dynamometer tests, presenting promissory results related to performance and efficiency of the combustion engine recovered to ceramic powder material.

Lightning is a high voltage and high current phenomenon and it originates by build up of electrical charge in the air or, more commonly, in clouds. It is constituted of an electric current peak of short duration (0,5 ms) and high intensity (200 kA), followed by a low intensity (400 A) but high duration (1s) periods. The lightning effects in aircraft can be divided in two groups: direct effects (physical effects such as melting, rupture, damage of surfaces and structures due to conduction of lightning current or high power magnetic force) and indirect effects (electromagnetic fields generating levels of transient voltage and current on interconnecting wiring and cable leads within the equipment circuits eventually damaging internal components).

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.