What 's the difference between Angle of Attack and Pitch? I am interested in knowing the theoretical and practical differences between the Angle of Attack (AoA) and Pitch: 


Graphical definitions
How are they related?
In what circumstances these angles are equal?
While flying, do you need to consider both or only the Pitch?


Thanks in advance :)
The reference of pitch is the horizontal. The reference of AoA is the direction of the relative wind.