IHS ESDU Estimation of airborne performance in landing. 91032

ESDU 91032 gives methods for estimating airborne distance for fixed-wing aircraft. The time taken is estimated as a function of the change in rate of sink between the screen and touch-down using a correlation developed from measured data for landings without significant float. This is directed towards certification style landings of transport aircraft, but some guidance is given for cases with significant float as well. A further empirical correlation allows an independent assessment of the time taken and of the speed loss during the manoeuvre to be made from the energy equation; the correlation provides the average value of drag minus thrust, again depending on whether there is a significant float or not. The ranges of aircraft types and flight conditions for which data were available are tabulated and cover a wide range of weights, geometry, approach angles and powerplants (turbo-jet, turbo-fan and turbo-prop). The correction of still air distance for the effect of wind and wind gradient is discussed. The geometric relationships that result if the path is prescribed to be some combination of circular arc and straight-line segments are given. Three worked examples illustrate the use of the method to determine the distance.