INTRODUCTION This Data Item outlines the test procedures implemented to design@ code and validate the various components of the ESDU Aircraft Performance Program. The programs considered are ? APP_01@ the Performance Program Pre-processor@ ? APP_02@ the Flight Performance Program@ ? APP_03@ the Interpolation Program. The Pre-processor (APP_01) is used by the Performance Program (APP_02) to interpret the input data. The Interpolation Program (APP_03) does not access the output of the Pre-Processor.