High intensity radiated field (HIRF) penetration in helicopters

Modern military and civilian aircraft use digital systems to control life-critical functions such as the engines, sensors, fuel systems and actuators. These digital flight control systems are vulnerable to external phenomena such as cosmic radiation, lightning, or high-intensity radiated fields (HIRF). Modern integrated circuits with higher densities and speed are more sensitive to HIRF. Also, composite materials, despite their advantages in strength, weight and cost, provide less shielding than aluminium. Because of these factors, the need to avoid digital upsets of electronic systems exposed to HIRF has become of great interest to industry and government agencies. Numerical simulation of HIRF penetration into a composite NASA scale helicopter model through the cockpit window was performed.