Out-of-Control Flight
Aerodynamic Principles
Loss of control of an aircraft can be a confusing and disorienting experience. If you are to recover, you
must make a rapid analysis of the specific phase of out-of-control flight. Visual and “seat of the pants”
cues are insufficient for you to differentiate between departure, post-stall gyration, incipient spin, or steady-
state spin.
Even the seemingly obvious determination of whether the aircraft is in an erect or inverted mode may not
be possible through sensory cues. In an erect spin, the aircraft may spin in a relatively nosedown attitude
with a high-g roll rate, or it may spin in a flat attitude with a high yaw rate and very little roll rate. In a
steady-state spin, the flight path is vertical, i.e., straight down. The axis of the spin, or the center of the
spin rotation, is also straight down.
In a steep nosedown attitude, the axis of rotation lies forward, and in some extreme cases the axis may be
forward of the entire aircraft. As the nose rises to a flatter attitude, the axis of rotation moves aft. If it
moves behind the cockpit, and if a high yaw rate is present, you will experience high transverse-g (“eye-
balls out”) forces (Figure 9). There is a possibility that you will interpret these transverse g forces as
negative g’s. The problem is further compounded when roll, pitch, and yaw oscillations vary in the direc-
tion and magnitude of g forces and literally tumble you about the cockpit.
DIRECTION
OF SPIN
Perceived as
Negative G
"Eyeballs Out" g
SPIN AXIS
Figure 9: G FORCES WITH SPIN AFT OF COCKPIT
Since you can’t rely on outside visual and sensory cues to determine the mode of flight, you must ignore
your intuitive responses. The only satisfactory means of analyzing the situation and, therefore, properly
recovering from out-of-control flight is by referencing instruments.
(9-98) Original
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