Zoom climb

A zoom climb or an unrestricted climb is a maneuver in which the rate of climb is greater than the maximum climb rate using only the thrust of the aircraft's engines. The additional climb rate is attained by reduction of horizontal speed. Before a zoom climb, the aircraft accelerates to a high airspeed at an altitude at which it can operate in sustained level flight. The pilot then pulls steeply upward, trading the kinetic energy of forward motion for altitude (potential energy). This is different from a steady climb, where the increase in potential energy comes from mechanical work done by the engines.

Zoom climbs are somewhat commonly performed by modern fighter aircraft and are typically referred to as "unrestricted climbs" in this context. Pilots will take off, accelerate to high speed at low altitude, and then pull the aircraft vertical or nearly vertical to quickly climb to the aircraft's cruising altitude.