INTRODUCTION

The methods presented in this Data Item are 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 1).

This Data Item provides simple methods for the reduction of take-off and landing measurements, i.e. the incremental adjustment of distances and speeds measured in "test" conditions to values applicable in some desired "standard" or "datum" conditions (see Reference 2).

The Item deals more particularly with aircraft that may be termed "conventional" and treats only of what are believed to be the main corrections. It neglects the influence of changes in the vertical thrust component in the reduction process. In deriving C_L it is assumed that L=W, i.e. the vertical acceleration and vertical thrust component are neglected.