Tim Capps wrote on Nov 20^th, 2013 at 11:01am:

What are these X, Y, and Z? I have noticed that, too, and I don't remember it from before. The No-TD-No-End-Of-Route seems to be a matter of tweaking, persistence and trying different things. With the tricks you've come up with, maybe their not the show-stoppers I once feared.

Not being in the industry, I have no idea for why they use the X, Y and Z suffixes. Looking at the entries in the iaps.db file, there is no difference at all between them, yet they seem to cause the CS FMC to have an error.

Take a look at these two for the Sydney (YSSY) ILS16L runway. I have put the difference between the two in bolt text:

{YSSY;RW16L;I16LY;CF16L}
04000;04000;0;0.0;0.0;0.0;CF16L;-33.742056;151.135603;0.0;IF;ISS;0.0;4;0;11000;;;0
04000;01920;0;0.0;0.0;7.0;FF16L;-33.856395;151.164650;155.0;CF;ISS;0.0;4;0;0;;;0
00067;0;0;0.0;0.0;5.8;RW16L;-33.951647;151.188842;155.0;CF;ISS;0.0;4;0;0;;;0
00600;0;+;0.0;0.0;0.0;;91.000000;181.000000;155.0;CA;;-1;4;0;0;;;0
03000;0;+;0.0;0.0;0.0;;91.000000;181.000000;125.0;CA;;0.0;4;0;0;;;0

{YSSY;RW16L;I16LZ;CF16L}
04000;04000;0;0.0;0.0;0.0;CF16L;-33.742056;151.135603;0.0;IF;ISS;0.0;4;0;11000;;;0
04000;01920;0;0.0;0.0;7.0;FF16L;-33.856395;151.164650;155.0;CF;ISS;0.0;4;0;0;;;0
00067;0;0;0.0;0.0;5.8;RW16L;-33.951647;151.188842;155.0;CF;ISS;0.0;4;0;0;;;0
00600;0;+;0.0;0.0;0.0;;91.000000;181.000000;155.0;CA;;-1;4;0;0;;;0
03000;0;+;0.0;0.0;0.0;;91.000000;181.000000;125.0;CA;;0.0;4;0;0;;;0

Unbelievable, but that's the only difference I found! To experiment, I'm going to get rid of one entry, and remove the I16LY or I16LZ from the one that I don't remove, to see what happens.

Just call me crazy for trying it. :D ;D ;)