Hi Bob,

Just to clear things up - For a positive fix using 2 NDB's

If the aircraft is 30nm to the north of NDB 'A' and NDB 'B' is 30nm to the west of the aircraft does that count as a positive fix?

The book and AIP does say "within 30NM of the aircraft".

Cheers Dan.

This is the sort of thing that makes me mad. I'm not sure if this came from a CASA question, but if it did it's a disgrace. Does 'within 30 miles exclude 30 miles? I believe that if you can't be 'within' 30 miles if you are 'at' 30 miles. Surely the people who write questions like this could find something more constructive to do with their time! If both NDBs are at 29.9 miles you can claim a fix, but if both are at 30 miles you cannot claim a fix. This is almost as stupid as the recent high court decision about dual citizenship!

In any case, apart from a 1950s full time fight navigator, who has ever even tried to plot a positive fix from two off-track NDBs while traveling at 3 miles per minute? Spare me!