And then there's that weird thing with 50ft DH and 125m RVR which puts it into the CAT IIIb domain (as it is less than 200m RVR) that 737s can do under certain circumstances (LAND 2 indication, all engines operating). And it seems that the DH for CAT IIIb with DH ops depends on ops spec and aircraft anyway, it's 20 ft for our bus fleets, not 25ft.