Aerodynamic Principles
Out-of-Control Flight
INVERTED SPINS
Inverted spins are an interesting and spectacular realm of flight; they are also a realm with which most
pilots are unfamiliar. Aerodynamically, the inverted spin is quite similar to the erect spin. The conditions
required to enter an inverted spin are:
1. Negative stalled AOA
2. Sideslip or yaw
The inverted spin, although not frequently encountered, can be extremely disorienting. A primary reason
for the disorientation, in addition to the negative load factors, is that in the inverted spin, yaw and roll are in
opposite directions. Because pilots are more sensitive to roll than to yaw, a pronounced tendency exists
for you to analyze the spin in the direction of the roll, instead of in the direction of the yaw.
RECOVERY
ANALYZE SITUATION
The proper recovery depends upon an accurate analysis of the situation. Faulty analysis and subsequent
application of improper control inputs can result in a worsening situation and loss of the aircraft. In order
for the aircraft to achieve a steady-state spin, it must go through a number of phases:
*
Stall: AOA above stall
*
Departure: loss of aerodynamic control
*
Post-stall gyration: AOA, turn needle, and airspeed oscillating
*
Incipient spin: AOA and turn needle pegged, airspeed oscillating
*
Steady-state spin: AOA and turn needle pegged; airspeed steady or oscillating slightly
(9-98) Original
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