Descent (aeronautics)

In aeronautics, a descent is any time period during air travel where an aircraft decreases altitude, and is the opposite of an ascent or climb.

Intentional descents might be undertaken to land, avoid other air traffic or poor flight conditions (turbulence, icing conditions, or bad weather), clouds (particularly under visual flight rules), to see something lower, to enter warmer air (see adiabatic lapse rate), or to take advantage of wind direction of a different altitude, particularly with balloons.

In a maneuver called autorotation, the pilot configures the rotors to spin faster driven by the upward moving air, which limits the rate of descent.

Very shortly before meeting the ground, the pilot changes the momentum stored in the rotor to increase lift to slow the rate of descent to a normal landing (but without extended hovering).

The aircraft would then dive at a 60-90° angle, holding a constant speed of 500 to 600 km/h (270 to 320 kn; 310 to 370 mph), until it had gone some 90% of the way to the ground, releasing its bombs at a minimum height of 450 m (1,480 ft).