Lightning and HIRF Transfer Functions Measurement Method used for A340-600 Certification

Georges Martins, AIRBUS Integration Test Center, Toulouse , France
Dominique Lemaire, AIRBUS Integration Test Center, Toulouse , France

Abstract

As part of the A340-600 HIRF and Lightning Indirect Effects Certification, measurements had to be carried out to determine the residual threats inside the A/C, for given primary lightning or HIRF (High Intensity Radiated Fields) threats outside the Aircraft.

The assessment of induced signals from these threats, consists in Transfer Function measurements. They are expressed as induced open-circuit voltages or short-circuit currents referred to injected currents on the aircraft, and are measured for different zones (wing, fuselage, THP, Landing Gear, Nacelle) and different types of electrical links.

The main particularity of the measurement method, is to work only in frequency domain and deduce the induced currents and voltages for standard applied lightning waveforms by Fourier Frequency to Time Transformation.

The purpose of this paper is to summarize the basics of the method used, sum up the measurement setups and the solutions eventually retained for practical injections and measurements, and synthesize the capabilities and limitations of the method.

The main interest of this approach is to use a unique measurement method for both HIRF and lightning needs and allow to perform on aircraft the certification tests with a whole campaign for both types of threats.

The method has also been developed with the additional objective to address both transfer functions needs with the same instrumentation. Moreover, a supplementary requirement has been to use only standard lab measurement devices such as Analyzers and medium power range amplifiers.