INTRODUCTION (Note: In this Data Item@ data options and facilities which are not available in the current release of the program are presented in italic script.) The facilities and the main calculation modules of the programs that make up the ESDU Aircraft Performance Program are described briefly in this Data Item. For more detailed information on the input and output variables and for examples of the input and output formats see Parts 4@ 5 and 6 (References 9@ 10 and 11). These programs are as follows ? APP_02@ the Flight Performance Program@ ? APP_03@ the Interpolation Program.