The ESDU Aircraft Performance Program is a suite of programs to predict the performance of an aircraft design for which appropriate aerodynamic and powerplant data are available. The programs are written in ANSI FORTRAN 77 and supplied both as source code and as compiled executable binary (*.EXE) files which at present run in DOS Windows under Windows 9x@ 2000 or NT. The suite of programs uses SI units internally. The user has the option to provide input in other sets of units or in mixtures of units. Output is in units compatible with the user input. The user can specify the input data either as constant values or as tables of data varying with a range of possible variables. Engine performance data can be accepted for several sets of jets and propellers having different performance per engine in each set. It is assumed that the engine data are applicable to ??fully-installed?? conditions (i.e. the data have been corrected@ for example@ for intake spillage@ base drag and aerodynamic interferences) but provision is made for additional thrust factors and incremental aerodynamic effects which can be functions of engine-dependent variables. The suite accepts both untrimmed and trimmed aerodynamic data. Routines are provided for trimming both conventional aft-tailed and canard designs. The documentation for the Flight Performance and Interpolation programs consists of the following Data Items. PART 1: INTRODUCTION (Data Item No. 00031) PART 2: INSTALLING AND RUNNING (Data Item No. 00032) PART 3: BRIEF GUIDE (Data Item No. 00033) PART 4: BRIEF FORM OF INPUT AND OUTPUT (Data Item No. 00034) PART 5: DETAILED INPUT AND OUTPUT (Data Item No. 00035) PART 6: EXAMPLES OF APPLICATION (Data Item No. 00036) PART 7: ERROR MESSAGES (Data Item No. 00037) PART 8: PROGRAM DESCRIPTION (Data Item No. 00038)