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In the EU FULMEN collaborative project a series of experiments based on AEA Technology’s Hawker Hunter airframe have studied coupling of E and dE/dt threats. Currents and fields were applied using either a low level lightning current simulator to the whole airframe, or by injecting the threats more locally. Coupling could be measured in two apertures at opposite ends of the airframe, in which cables were routed both parallel and perpendicular to the current paths. The different configurations for measurement and test allowed the various coupling methods to be separately elucidated. Likely levels of E-field and d2B/dt2 coupled transients which could couple to internal equipment are discussed in relation to the present consensus of external environments.

DO160D/ED14D S 22 describes procedures for pin testing; they define a specific source impedance for the transient generator. This inevitably limits the maximum current that can be driven into a pin during a test. Sometimes this implied current limit has been questioned as being too high since s/c currents associated with Waveform 5A have a lot of energy and can damage components. This paper reports investigations into actual current levels that can occur particularly when transorbs installed for protection purposes become conducting. Theoretical estimates and results of experiments are described. For Waveforms 4 and 5, the currents can be estimated for simple circuit equations. In some circumstances the current limits could be set too low so the procedures need to be carefully reconsidered during DO160D testing.