"INTRODUCTION Spoilers may be used on both upper and lower surfaces of wings@ but they are used most frequently on the upper surface. A ""spoiler"" attached to the upper surface of a wing will cause the flow to separate@ literally ""spoiling"" the flow@ and usually resulting in a loss of lift and increase in drag. The spoiler is usually a device that can be actuated very quickly. These three attributes@ i.e. loss of lift@ increase in drag and rapid actuation@ lead to a variety of uses or potential uses on aircraft. These include use (a) as roll control@ (b) for lift dumping@ (c) as an airbrake@ (d) for direct lift control (DLC)@ i.e. controlling lift without change of attitude@ (e) for load alleviation@ (f) as a means of reducing the hazard of trailing vortices to following aircraft. Spoilers also have other@ non-aeronautical uses@ such as the prevention of overspeeding of wind turbines. Spoilers may be placed at any chordwise position@ have various spanwise extents@ and be used in isolation or in combination with flaps and ailerons. The parameters of interest will depend upon the particular application. In addition to steady lift@ drag and rolling moment there may be interest in the time varying characteristics (for (e) above)@ in pitching and yawing moments@ and in the hinge moments and power required for actuation. This Item presents a method for predicting the lift and rolling moment due to upper-surface spoiler deflection@ but without trailing-edge flap deflection@ the effects of which are covered in Item No. 92002 (Reference 48). The method is based on information contained in Derivations 1 to 32. Additional useful descriptive or supplementary information is contained in References 33 to 47."