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Vol. 9 No 4 August 2001 

Lightning Protection & Testing

The modern aircraft are vulnerable to effects of lightning due to the increasing use of Lightning strike to LCA modelsensitive electronics and composites. These effects can be broadly classified into direct and indirect effects. The direct effects are the physical damages caused at lightning attachment points, hang on locations and along the current flow paths. They usually include high voltage and high current related damages to aircraft structure and other hardware, such as local burn-through, splintering/shattering, puncture of dielectrics, tufting of composites, fuel ignition, etc. The indirect effects are caused by the electromagnetic fields of lightning. They include temporary upset/malfunction and/or permanent damage to various electronic/electric circuitry. A lightning strike at a distance away from the aircraft can also produce the indirect effects.

The dangers that can arise from lightning strikes must be borne in mind by those concerned with all aspects of aircraft design. Protection, if considered  early enough in the design, can be built in at less orwith no penalty in weight and cost. DRDO has established a Lightning Test Facility (L TF) with high impulse Interaction voltage and current generators to test the lightning worthiness of aircraft through well-designed experiments and testing. This indigenously designed and built facility is one of its kind in the world and can also be used for commercial testing and certification of the components of HVDC power transmission lines.