ESDU 88040 describes a Fortran program@ provided on disc (uncompiled) in the software volume as ESDUpac A8840@ that determines the aileron rolling and yawing moment coefficients for an aircraft. The program implements the empirical methods of ESDU 88013 and 88029@ accessing the graphical data in digitised form. Those documents must be consulted to establish the limitations of the program in terms of the geometries and flow conditions over which the methods were tested and the accuracy achieved. ESDU 88040 describes the input required by the program and illustrates the output through a worked example. The source code is provided on disc in the software volume accessible under MS DOS.