INTRODUCTION The method presented in this Data Item is suitable only in the early stages of a design project. It is also assumed that the tyre-runway friction interaction is dealt with in an approximate way using gross assumptions: other Items in the Performance Series provide more comprehensive methods (see@ for example@ ESDU 05011@ Reference 2). This Data Item contains formulae for the estimation of take-off distance over a screen@ usually of height 35 ft (10.7 m) or 50 ft (15.2 m). Information on the calculation of accelerate-stop distances is also included. The methods apply to all types of propulsive unit. For some general considerations of the take-off problem@ see Reference 3. A useful summary of methods for estimating take-off distance will be found in Reference 4.