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.