Russel,
WELCOME TO THE AWS WELDING FORUM!!Back up, slow down, take a deep breath... Relax,...
Now, the black area, is that a completed fillet weld for sub Assy A?
Are the sub assymblies welded on both sides of the corner joints?
Does the square butt weld fill in the white area between sub assy A & B? Thus .71" wide by about .5" deep?
If I am seeing what I think I am seeing it is more properly a groove weld, not a butt weld. Now, groove welds are often used to weld butt joints. It appears they have called out the 'joint' leaving the exact 'weld' to the fabricators discretion.
Does it get welded along the side where the members faying surfaces are in tight contact? The welding symbol does not indicate an all around condition.
If it is such a groove weld to complete the assymbly then it can be accomplished without a PQR from Clause 4 because you can do it using one of the Pre-Approved designations from Clause 3.
But, I am not totally certain as to what I am looking out and what you are dealing with. More information would really help, at least for me.
Have a Great Day, Brent