This contribution presents a fast simulation technique of eddy current testing (ECT) signals due to narrow cracks embedded in a planar stratified medium. Starting from the Boundary Element Method (BEM) approach for ideal and narrow cracks, a collaborative work by the authors has led to the development of a more general semi-analytical model treating several parallel and/or orthogonal narrow cracks embedded in a planar multilayered structure, without any constraint on the numbers of layers or flaws. Simulation results obtained with this method have been compared with experimental data, results from literature and Finite Element Method (FEM). The theoretical approach and results obtained are presented and some perspectives for further extension are discussed.