Originally Posted by
deltafox44
It's said that angle of attack disagree was 22°5 (at least on Lion Air). But the AoA vane does not directly measure angle of attack, but angle of airflow around the fuselage, which is higher - about twice the angle of attack - due to aerodynamics around a long body
That means the error at the Angle of Airflow vane was not 22°5 but about 45°, which correspond to the angle between AoA screws.
I don't believe I really get this point. It sounds OK if indeed the airflow was not parallel with the fuselage at some locations. But why wouldn't the streamline effects be well known beforehand from wind tunnel testing and the AOA vanes located at a point where the lines are truly parallel?