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Numerical simulation of indirect effects of lightning on a multibranched engine control wiring harness set was developed using the MHARNESS* simulation code. Electrical parameters of the harnesses and subassemblies were measured and entered into the analytical model. Results of the analytical model for bundle current distribution and harness attenuation for a lightning pulse were compared against actual test data. Close correlation was obtained in most branches. Further work to optimize the model and add sensor and actuator loads will be conducted in the near future, and sensitivity analysis will be performed on various harness parameters and bonding impedance.

Successful lightning protection design is important for the CargoLifter CL 160 large non-rigid transport airship. Non-rigid airships, like balloons, have few hard structures so alternative means need to be designed to collect and conduct lightning currents. The helium lifting gas ionizes at one third the field intensity required for air so spark formation in ambient electric fields is more likely to originate inside a helium filled envelope than in the air outside of it. Protection development is being accomplished by a combination of high voltage strike attachment tests on scale models, and numerical analyses of electric fields.