Why no stepdown fix in GPS?

Roy Smith wrote:

In article , wrote:

Roy Smith wrote:

I flew the KFWN VOR or GPS-A (http://204.108.4.16/d-tpp/0506/05412VGA.PDF)
this morning with a CNX-80. Annoyingly, ANKLE (the stepdown fix) is not in
the database. You get SAX-MAGLV. It seems like SAX-ANKLE-MAGLV would
make a lot more sense. Is the some reason it's left out of the database?

It's an overlay, so someone at Jeppesen made a coding judgment to treat it as
an ATD stepdown fix.

What's "ATD"?

It's in the AIM (many times ;-) "Along track distance

From AIM 1-1-19.13:

13. Unnamed stepdown fixes in the final approach segment will not be coded in the
waypoint sequence of the aircraft's navigation database and must be identified
using ATD. Stepdown fixes in the final approach segment of RNAV (GPS) approaches
are being named, in addition to being identified by ATD. However, since most GPS
avionics do not accommodate waypoints between the FAF and MAP, even when the
waypoint is named, the waypoints for these stepdown fixes may not appear in the
sequence of waypoints in the navigation database. Pilots must continue to identify
these stepdown fixes using ATD.