INTRODUCTION This Data Item shows how the programs that make up the ESDU Aircraft Performance Program are initially installed and run. 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 use the Pre-Processor. The programs are written in ANSI FORTRAN 77 and supplied both as source code and as compiled@ executable@ binary (*.EXE) files (for Windows 9x or Windows NT). The compiled files include date and time routines which add messages to the output files. The compiled files run in DOS windows in the Windows environment.