Visual Angle of Attack Indicators and Systems Engineering Theory
If VAOAI is primary, then failure mode remedies must be determined, published, and trained. Pretty soon, the solution will come to pitch and power to determine approximate airspeed. Back when I gave primary instruction, I wouldn’t solo a student till they had an hour of pattern work with the airspeed indicator covered. They were terrified on the first approach, apprehensive on the second, and by the end of the hour, bored stiff. They were ready to handle an airspeed failure.