AOA Indicator.
The AOA indicator (24, Figure FO-1) is placarded ANGLE OF
ATTACK. The scale is calibrated from 0 to 30 arbitrary units,
in single unit increments, increasing in a CCW direction. Reference
marks are provided as follows: At
15.6 scale units a rectangular
maximum range index; at
17.5 scale units a triangular
maximum endurance index; at 20.0 scale units a T-shaped approach
index; from 23.1 to 24.1 scale units a striped stall warning
index. The red (OFF) flag will appear at the 3 o’clock position
when the unit experiences a loss of power.