If an aircraft descends below the circling minima to the runway minima prior to becoming visual, either a landing straight ahead or a missed approach must be conducted.
The option of circling to another or even the same runway is not available.
The reason is that the runway minima is always lower than the circling minima because the obstacle clearance area is smaller if visual circling is not required to join final for the selected runway !!!!!!!!
[ With thanks to Chris Henry who I did my CPL training with many years ago and who used to produce an excellent CIR book ].
Flopt
PS in ignorance contemplated something similar at YKRY ten years ago in a Baron and worked out very quickly that it was a very unwise thing to try.
