Since the rhumb line is on the Equator side of the great circle this
must be the northern hemisphere. If the conversion angle is 3º then convergency
is 6º. If the great circle track from A to B at B is 080ºT then at B it is
086ºT. If the great circle track from A to B at B is 086ºT then the great
circle track from B to A at B is the reciprocal; 086º + 180º = 266ºT.