"Roy Smith" wrote in message
...
| What were you flying? In a spam can doing 120 kts (which is the
| environment most civilian instrument is done in), the turn radius is
| pretty small. If you're flying a jet, leading the turn may be the only
| way to avoid blowing out the side of the airway on sharp turns.
|
| Another factor is that up until a few years ago when GPS started to
| become ubuiqitous, most instrument trainers had no DME so a full TO/FROM
| reversal way the only way to be sure you had reached the fix. If you
| have DME or GPS and thus accurately know your distance to the fix, I
| don't see any reason not to lead the turn.

I was in C-130s. Now I fly a C-206, almost twice as big. :-)

Or, as my brother says, "Once a trash hauler, always a trash hauler." (He
prefers sleek little experimental.)

Even at 120 knots your turn radius is more than half a mile
(0.63661977236758134307553505349006 mile, to be a little more accurate).

By the time your TO/FROM flag has flipped you have probably gone at least
half a mile beyond the fix. So now you are a mile off course. In a C-130 you
could probably triple that -- I always planned my turns for a 2 mile radius
and it worked out pretty well. In the Cessna 206 I start my turn about half
a mile before the fix if I can. Those GPS units that give you turn warning
and show the turn radius on their moving maps seem to lead the turn about
half a mile, too.