ARROW project aims at developing a numerical methodology and a SW tool to model indirect effects of lightning on cable-harness configurations installed aboard aircrafts made of composite materials and equipped with a “current return network” (ALEEN, ALmost Equipotential Electrical Network). The Tool shall be able to:• input geometry and material properties of the aircraft and of ALEEN from CAD (CATIA);• input harness “space allocation” areas from CAD and input cable-harness representation from SGO WP Leader DB• define lightning entry/exit points and waveforms, model the electromagnetic interactions between lightning and aircraft/ALEEN and evaluate E and H near-field induced on sampling points into the “harness space allocation areas”• interface the MTLN (Multiconductor Transmission Lines Network) based code named CRIPTE by providing it the equivalent Vs and Is distributed generators, from proper elaboration of the E and H fields• run CRIPTE to evaluate Voc (Open Circuit voltages) and Isc (Short Circuit currents) at equipment terminals.For any critical situation with respect to the EM compatibility to lightning threat the Tool will be able to allow modifications of the harness (different routing, improved shielding…) and to effectively repeat Voc and Isc evaluation up to a safe configuration is found. A 3D full-wave solver based on PEEC method (Partial Element Equivalent Circuit) for the modeling of the lightning-aircraft interactions and the evaluation of E and H, well-conditioned for the involved low-frequency range (from DC to some MHz), will be delivered. The computational modules will be integrated, together with pre-processing and post-processing modules, into a SW CAE tool named “ALEEN-L Modeling Tool” providing user-friendly working procedures, projects management, data storing and data navigation. A general “client-server” HW configuration will be allowed. The procedure will be validated against experimental data measured on an SGO WP Leader mock-up.