These lights furnish the landing signal officer
and the pilot with an accurate indication of
indicator displays a continuous visual indication
approach angle of attack during landing. An
of the local angle of attack. A typical angle-of-
angle-of-sideslip system, consisting of an
attack system provides electrical signals for
airstream direction detector, angle-of-attack, and
operating the rudder pedal shaker. The shaker
warns the pilot of an impending stall when the
angle-of-sideslip compensator, is installed on
some aircraft. The outputs from these are used
aircraft is approaching the critical stall angle of
for controlled rocket firing.
attack. Electrical switches in the AOA indicator
The angle-of-attack indicating system consists
operating at various preset angles of attack
energize colored lights in the approach light
system and an approach index light in the cockpit.
direction detector measures local airflow direction
relative to the true angle of attack. It does this
by determining the angular difference between
local airflow and the fuselage reference plane. The
sensing element works with a servo-driven
balanced bridge circuit, which converts probe
positions into electrical signals.
T h e angle-of-attack indicating system
operation is based on detection of differential
pressure at a point where the airstream is flowing
in a direction that is not parallel to the true angle
of attack oft he aircraft. This differential pressure
is caused by changes in airflow around the probe.
Figure 6-28.-AOA indicators: (A) radial; (B) vertical scale.