Tired. The CAA on the IRT expects you to track VOR and ADF radials to the same accuracy. Just because it is easier to select the radial and fly the beam bar on a VOR doesn't mean you can't do it on an ADF/NDB set-up (point about NDB accuracy noted). Flew this departure the other day (in LNAV) but monitoring the CHT NDB, which didn't move from 067. As it is acceptable to fly the 057 to CHT, why not the 067 the other side? I think we are too accuracy conscious these days, having GPS and the like navigating us to within a couple of metres, but the system doesn't need to be that accurate. If it did, we would all have to fly double FMC, DGPS aircraft, etc, but we don't.