Lightning Protection on Advanced Fighter Aircraft 700930

The lightning design challenges and protective measures being used or considered for use on late models of the F-4 Phantom II aircraft, advanced air superiority aircraft and electronic flight control systems are presented in this paper. Ideally, if an aircraft were constructed of high electrically-conductive material and had no electromagnetic openings in the skin, lightning would strike one area and leave by another without damaging the aircraft. For practical aircraft protection, lightning discharges must be prevented from entering the aircraft interior and damaging electrical and electronic systems, causing possible fuel system explosions, and affecting crew capabilities. Openings in the aircraft skin such as radomes, canopies, camera windows, navigation lights, fuel vents, composite materials, atmospheric sensors and unbonded sections all reduce the capability of aircraft to withstand lightning strikes. Unfortunately, advanced fighter aircraft incorporate all these electromagnetic openings. Additional lightning protection requirements have been necessitated by the introduction of electronic flight control systems (a replacement for the mechanical linkage and wire rigging used in present aircraft). Even a temporary loss of electrical power or an induced transient in an electronic flight control system would present a serious flight hazard. Since the system effectiveness of advanced fighter aircraft depends upon increased accuracy and range of their Fire Control Radars, present day methods of radome protection using metallic strips are not usually acceptable. Size, weight, crew visibility, and corrosion prevention are other items critical to high performance fighter aircraft with which lightning protection must be made compatible.