Accelerated stalls are defined as those stalls entered at load factors greater than 1.0 g. The amount of
prestall buffet warning during accelerated maneuvers varies with mach number and altitude. In general,
the warning margin is greatest at about 0.60 IMN. The buffet boundary is clearly defined and provides a
good warning of the stall at all attitudes. Below about 0.40 IMN, the buffet onset occurs nearly at the
maximum turning performance of the aircraft. Recovery is immediate with the release of back stick
pressure. The presence of wing stores increases the severity of prestall buffet; however, the characteris-
tics are otherwise similar to those of a clean configuration.
Directional departures can be caused by excessive or abrupt rudder application at low to moderate
airspeeds and are insidious because of the limited warning of the impending departure. As discussed in
Chapter 1, departures occur at a lower angle of attack when sideslip is introduced. The directional depar-
ture is characterized by an abrupt pitchup, followed by one to two snap rolls in the direction of the applied
rudder. Neutralizing flight controls will effect immediate recovery.
WARNING: Intentional directional departures are prohibited at airspeeds greater than 160 KIAS to
avoid possible overstress.
VERTICAL MANEUVERING AND DEPARTURES
Vertical, low airspeed departures are generally mild and will take one of two different forms. If the pitch
attitude is less than 90 degrees, the aircraft will pitch abruptly forward; if over 90 degrees, the nose will fall
slowly backward. In some cases, with the pitch attitude just over 90 degrees, the aircraft will back down
on its tail (tail-slide).
WARNING: During testing, approximately half of the tail-slides resulted in engine anomalies, such
as engine surges, locked-in surges, or flameouts.
During flight tests, approximately 10% of the tail-slides resulted in an inverted spin. Although entering an
inverted spin is unlikely even after a tail-slide, you should avoid maneuvering within 20 degrees of the
vertical, when less than 100 KIAS, to prevent the possibility of a tail-slide.
WARNING: Intentional spins and tail-slides are prohibited.
If you hold the control inputs after the aircraft departs controlled flight, the aircraft will continue to oscillate
about any or all axes in increasingly nose low attitudes. From a 1.0-g departure, these oscillations are mild
with roll in the direction of applied rudder. Post-stall gyrations resulting from accelerated stalls are similar
except that initial roll rates will be higher. In either case, neutralizing the controls will effect rapid recovery,
normally in a nose low attitude. AOA and airspeed must be checked to determine when to start pullout.