Bookworm has it.
I can understand why there is a problem with the circling minima. It is because the explanation given in some text books get it wrong.
From a practical point of view, let's use Newcastle NDBDME 25 and assume that there is no approach available at the other end.
We will apply the recomended 200ft addition to the IR minima.
In this example, the IR minima are;
OCH 371 for straight in
OCH 534 for a circle to runway 07
That makes the IMC minima
OCH 600 for straight in; and
OCH 734 for a circle to runway 07
If we intend to circle, we will level at our OCH of 734ft. If we are not visual at the MAP, we will execute a missed approach.
The biggest reasons for not descending to the straight in minima and climbing back to the circling minima are;
a) We could be below the height of obstacles to the side of the runway; and
b) With the nose in the climb attitude, our view is reduced forward. i.e. Having spotted the runway ahead in a low wing aircraft, the last thing we want to do is a climbing right turn.
I would also recomend that pilot considdering a circling manoeuvre considder adding something to the visibility minima. Trying to circle at an unfamiliar field in 1nm visibility is hard work especially for the inexperienced.
Also be sure that one knows how to start the published missed approach procedure from anywhere in the circling procedure.
Finally, if using 600ft OCH, one will reach that height 2nm from the runway on a 3deg approach path. With 1800m visibility, one will not see the runway from that height until 1nm from touchdown. Can you safely land straight in using your aircraft starting descent from 600ft 1nm to the threshold in poor visibility. Try it VFR and see how hard it is! Note I am not saying that you should use 3600m but perhaps 1800m would be challenging initially.
Regards,
DFC