INTRODUCTION Standard loading sequences are available for simulating the magnitude and frequency of the applied service loadings of particular components or structures. These sequences are primarily used in the comparison of fatigue performance of different materials or components under various conditions. They are also used for the evaluation of fatigue data for preliminary design@ the evaluation of fatigue life prediction models@ assessing the degree of scatter in fatigue life data and other related evaluation and comparison exercises. This Data Item describes three standard loading sequences for use in the fatigue assessment of aircraft structures: TWIST (and Mini-TWIST)@ FALSTAFF (and ENSTAFF) and Helix/Felix. A description and analysis of each of the standards is given.