Originally Posted by 433
...the thread seems to have got lost in the definition of "own navigation" rather than the use of the word "direct".
I think you're quite right on that point - but that's the interesting bit.
As long as the word 'direct' is used I agree the pilot should follow the shortest line to the fix - nowadays sometimes we need to think great circle which raises some other issues, but essentially direct means straight line to wherever is specified.
But 'own nav', without specifying direct or a particular point, means different things to different people and some of the interpretations are surprising...and interesting. I doubt that we will see an internationally agreed meaning for 'own nav' in specific situations any time soon. So, for me, the really interesting part about this thread is just how important it is to use unambiguous clearances - i.e. to state direct and to where when I mean direct and to be very wary of clearing an aircraft on own nav if I'm not going to be able to keep a careful eye on it (=very rarely!).