The JAA circling approach allows you to lose visual contact with the field as long as you stay within the circling area and above circlng minima for the sector you are in until you become visual.
Curiously, where does it say that?
PAN OPS Doc 8168,
7.2.2 After initial visual contact, the basic assumption is that the runway environment should be kept in sight while at minimum descent altitudeheight (MDA/H) for circling. The runway enviroiunent includes features such as the runway threshold or approach lighting aids or other markings identifiable with the runway.
and
7.4.1 If visual reference is lost while circling to land from an instrument approach, the missed approach specified
for that particular procedure must be followed. The pilot will make an initial climbing turn toward the landing runway
and overhead the aerodronie. At this point, the pilot will establish the aircraft climbing on the missed approach hack.
I'm not quite sure of the relationship between JAR-OPS and the above document....