Because of the complexity of aircraft SMCs (sheet metal components)，there is no suitable pubilc domain software available for its FPD (flat pattem development)．The special features of aircraft SMCs are analyzed．An automated FPD system for aircraft SMCs based on CATIA is designed and developed．A set of unique development algorithm comprising of normal cross-section and joggle development techniques is provided．An example is given to illustrate the development of the component．