Biaxial bending on columns

[Mixtli]

Hi everyone,
Please refer to the attached.
So the stress make the cross section bend about one line, that could possibly be the NA.
But a) I drafted the moment vectors and the resultant and b)drafted a line between the centroids of the compression and tension stresses an both are co linear, which is consistent with the forces applied to create those stresses.
Judgement says that the NA should be perpendicular to the resultant moment. The thing is that this NA is totally different from other NA (From stresses diagram)

What am I missing here?

Thanks a lot guys

M.

 

[Mixtli]

Thanks for the clarification Doug.
Ya I know BA I just thought.....

Cheers