The higher the aileron deflection, the higher the dihedral effect. Since both the aileron and rudder are deflected during a steady sideslip, this measure of directional stability and dihedral effect can only be an approximation. Directional stability and dihedral effect can be determined more accurately by analyzing dynamic maneuvers. This is a potentially hazardous situation for a multi-engine airplane where the loss of an engine on one side will require large amounts of rudder deflection to maintain straight and level flight. For normal flight conditions there is little reason for a pilot to intentionally sideslip an airplane.
Intentional sideslips are then necessary to keep the airplane over the runway just before touchdown.
It is a measure of how easily the pilot can compensate for crosswinds during landing. Specific Objective of the Test Determine the gradient of rudder deflection per degree of sideslip, and aileron deflection per degree of sideslip for one flight condition. The steady sideslip is used as a flight test maneuver to measure directional stability and dihedral effect over most of the flight envelope. The steady sideslip is used additionally as a measure of crosswind capability for the landing and takeoff configuration. In most cases the amount of sideslip that can be commanded by the pilot is limited by the amount of available rudder deflection.