Aero Chapter 03, High AOA/Stall/Spin
T-45 Aerodynamics Student Workbook
RUDDER BLOWOUT
Rudder blowouts occur because the rudder control system is reversible and sideslip angles as little as
15 degrees in a post-stall gyration or spin may produce airloads that fully deflect the rudder. The pilot
may need to apply considerable force on the rudder pedals, in excess of 250 pounds, to center the rudder
(Figure 59).
RUDDER
AIRFLOW
Figure 59: RUDDER BLOWOUT
SPINS
A spin is an aggravated stall condition with autorotation describing a helical path. Autorotation is a steady
state, self-sustained mode that is a combination of roll and yaw caused by an asymmetric stalled condition
on the up-going and down-going wings. If the aircraft were nosedown, the motion would be pure roll. If
the aircraft were flat, the motion would be pure yaw. In most cases, anticipate a confusing combination of
both.
An aircraft will not normally enter a spin from a wings-level stall. A spin is initiated by holding pro-spin
controls after the stall which introduces a yawing moment that produces a roll. The two things necessary
to enter a spin are:
Stalled AOA
Yaw
T-45 SPINS
The T-45 is highly resistant to upright and inverted spins. The pilot should determine whether he is in a
PSG or a spin before applying anti-spin controls. Inadvertent entry into any spin mode is possible during
recovery from a spin, nose-high vertical maneuvering, maneuvering near full forward stick, a sustained
cross-controlled roll, or a sustained high AOA roll.
(7-99) Original
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