Qualification and certification of helicopters to military and civil high intensity radiated field (HIRF) requirements

The EMC High-Intensity Radiated Field (HIRF) requirements for a modern helicopter are some of the most severe for any aircraft. These reflect the ability of helicopters to hover for long durations while exposed to high-level electromagnetic fields combined with low-level flight and the ability to fly into areas traditionally avoided by fixed-wing aircraft. These sources of radiation are now prevalent in normal operation both within the civil and military operational environment and the latest requirements reflect the need to clear rotorcraft to very high field strengths. Furthermore, with the contraction of the helicopter market there is trend towards joint military and civil programmes, with the consequent need to qualify and certify a given helicopter type to both military and civil environments. This paper presents a helicopter manufacturer´s perspective on the HIRF clearance process. It details some of the lessons learnt and proposes a unified approach to military and civil clearance. Furthermore, it discusses the key issues that need to be addressed by the industry at large in order to obtain a more cost effective means of meeting the demanding HIRF requirements