"The required staffing is Tactical, Planner and Assistant. ALL the time. If one is not present, for whatever reason the sector must be closed. That is the procedure. Seems pretty sensible to me, post Ueberlingen."
Yes that is the current procedure. However, there is a draft SI in the ops room proposing that if one of the ATCOs goes sick, and there is no sick cover rostered, the sector will be run by the remaining two ATCOs using combined T & P for breaks rather than closing the airspace. It is this draft SI that seems to have inspired this thread.