Refer to figure.
The lateral static stability is a measure of the airplane’s tendency to return to the wings-level attitude after a disturbance has caused the airplane to be disturbed in the rolling plane.

Positive lateral static stability is the tendency of the airplane to roll to the left with a positive sideslip angle, nose to the left. Its ability to recover is dependent on the effect of sideslip.

A disturbance in the rolling plane causes the angle of attack of the upgoing wing to decrease and the angle of attack of the down going wing to increase. Provided the airplane is not flying close to the stalling speed, then the upgoing wing produces less lift than it did before the disturbance and the down going wing will produce more lift than it did. Together, these changes result in a rolling moment in opposition to the initial disturbance and have a ‘roll-damping’ effect. When the roll damping exactly matches the aileron torque the airplane has a steady rate of roll.

The airplane design features that increase the lateral static stability are:

• wing dihedral.
• sweepback.
• high wing mounting.
• increased effective dihedral.
• large, high vertical fin.
• low CG.

The airplane design features that decrease the lateral static stability are:

• wing anhedral.
• forward-swept wings.
• ventral fin.
• low wing mounting.
• extending inboard flaps.