Originally Posted by
Mad (Flt) Scientist
It certainly can be., if you define it that way.
On aircraft with a fuselage mounted AOA sensor, it makes sense to use the fuselage as the reference, not some hypothetical wing chordline. Which is moving around and varies along the span as well.
The AOA definition used for 2D sections isn't very transferable to a full aircraft.
I agree, the presence of wing twist and variation in section to account for spanwise flow changes makes wing sections a less desirable reference on an aircraft.
Pitch is still not AoA even if referenced to the fuselage because AoA includes both vertical and horizontal oncoming relative wind components. An aircraft operating at a certain pitch can have differing AoA readings from horizontal to climbing to descending flight. A plane may remain in a stall at 25 degrees pitch and, as horizontal airspeed bleeds off, convert from 25 degrees AoA to the unfortunate nearly 90 degree AoA.