On Sunday´s I think a NCL based machine does NCL BFS STN BFS NCL. Prior to christmas on this schedule (ie winter 2009/10) this was the case when I flew BFS STN, the pilot advised that NCL Crew were working on the flight.
There are some surprising W patterns these days, On Tuesday a LGW crew did
LGW BFS BCN BFS LGW!
EI-BUD