view. Lag pursuit Lag pursuit is used to stop or reverse closure rate and to decrease AOT, while allowing the attacker to maintain or increase forward separation (also called nose/tail separation, or nose-to-tail). Following outside the defender's turn radius, the attacker can maintain or increase energy while forcing the defender to turn at an energy depleting rate. "Hot side" lag occurs when there is a large amount of forward separation between aircraft, showing the top side of the defending fighter. This puts the attacker in the defender's rear view, and the common defense is to tighten the turn. "Cold side" lag occurs when there is little nose-to-tail separation, leaving the belly of the defending fighter in view. This puts the attacker in the defender's blind spot, and the common defense is to reverse the turn. Unless the defender is markedly more maneuverable, and lateral separation is just right, lag pursuit can not be maintained for long, causing the AOT to decrease until a suitable firing solution is presented. Out-of-plane maneuvers Maneuvers are rarely performed in the strictly vertical or horizontal planes. Most turns contain some degree of "pitch" or "slice". During a turn in an oblique plane, a pitch turn occurs when the aircraft's nose points above the horizon, causing an increase in altitude. A slice turn happens when the nose points below the horizon, causing a decrease in altitude. The purpose is not only to make the aircraft harder for an enemy to track, but also to increase or decrease speed while maintaining energy. An out-of-plane maneuver enhances this effect, by diverting the fighter into a new plane of travel. Increasing the pitch or slice can quickly provide a change in speed, which can just as quickly be reversed by returning to the original plane of travel. Out-of-plane maneuvers are not only used to provide a reduction in turn radius, but also causes the fighter to fly a longer path in relation to the direction of travel. A maneuver such as a high Yo-Yo is used to slow closure and to bring the fighter into lag pursuit, while a low Yo-Yo is used to increase closure and to bring the fighter into lead pursuit. During an out-of-plane maneuver, the attacker's nose no longer points at the defender. Instead, the aircraft is rolled until its lift vector (an imaginary line running vertically from the center of the aircraft, perpendicular to