The drive file, supplied by the user, contains sequential turning points describing the signal to be applied. The list of peaks and troughs is in ASCII format. During the test, haversines are generated to join these points. The waveform can be generated either at a constant frequency or at a constant gradient.

There is an option of running spectrum loading with or without crack monitoring. During testing, there would be two on-line plots, one showing requested and achieved load levels, the other showing the crack growth. Crack monitoring would be either in micro-volts or crack length in mm, or both.

Final presentation of data would be in the form of an ASCII text file giving no of flights against crack length, with the crack length increasing by a preset increment.