dynamic deceleration, referring to the way the plane loses speed during the maneuver. In a similar manner, the Syrians apparently called the maneuver the Zero speed maneuver (, "Munawarat alsureat sifr") during their usage of MiG-21F-13s and the like. Maneuver description The maneuver can simply be described as; a rapid vertical pitchup from level flight without initiating a climb, followed by a forward-pitch back to level flight. If properly performed, the plane maintains nearly straight flight throughout the maneuver. The plane does not roll or yaw in either direction. This greatly lowers the speed of the aircraft due to the un-aerodynamic under-surface of the aircraft going against the airflow. To perform the cobra, the maneuver must be entered from fairly high subsonic speeds. Proper entry speed is necessary because, if the maneuver is entered too slowly, the plane might be unable to complete the maneuver or return to level flight with sufficient speed, while entering at too high a speed would create g-forces so high that the pilot loses consciousness or the airframe is damaged. High thrust is also needed throughout the maneuver to not stall out. To execute the maneuver the aircraft only needs to use its standard aerodynamic controls, however executing it can be achieved more easily with the addition of modern thrust vectoring. Aerodynamics The cobra maneuver requires more than just pilot input and aircraft maneuverability to be performed. Since the maneuver requires the aircraft to not lose or gain substantial altitude during the maneuver, the change of alpha during the vertical pitchup has to be fast enough to break the airflow of the wings, as to not make the aircraft climb. To be able to perform this rapid vertical pitchup the aircraft needs an "aerodynamic instability" in its core aerodynamics which will make the aircraft rapidly pitch up by itself once the elevator of the aircraft is pitched to the point where it breaks the airflow during a pitch up; but also post-stall control and stability to not enter an uncontrollable stall at the peak of the pitch; which then allows the aircraft to center the elevator and using the torque from the elevators added drag to pitch forward and make an aerodynamic recovery to horizontal flying again. Only specific aircraft feature this "instability" and thus the maneuver can only be performed by a small number of aircraft models. This is because conventional aircraft are designed