ESDU 89010 gives calculation sheets for estimating hinge moment coefficients for trailing-edge controls on a wing, tailplane or fin. Values to be entered on the sheets can be extracted from other ESDU documents in the Series, and the calculation is divided into four steps. The first sheet gives the routine for the two-dimensional characteristics, which may include the effects of a nose or an Irving internal balance. The next sheet deals with establishing the three-dimensional values of the derivatives using the values from the first sheet. The third sheet calculates the increment to the derivatives from a horn balance and the last sheet provides the procedure for treating the effect of a tab. A worked example illustrates the use of the calculation procedures.