I was surprised that when I entered the RNP approach to KPSP (Palm Springs) 13R into the MCDU, the magenta line was perfectly drawn on the ND according to the approach chart. I tried the same with the opposite runway direction 31L, but the result was disappointing (narrow curve, bypassed waypoints etc.). I changed the STAR file to overfly the RNAV waypoints, but the magenta line then was laid out in a zig zag pattern, there were no smooth curves.I guess the missing piece to form an RNP approach to 31L is "arc to fix" or what it's called so that the MCDU would produce a line that corresponds to what's on the approach chart.I know that RNP isn't implemented in the MD-11 (is it in any other FSX plane?), but I wonder why in one case the route on the ND looks exactly what's on the approach chart (13R), in the other case it seems not possible to form the required route (31L). Are there any keywords for the STAR files that can be used to "simulate" RNP procedures?

You may create additional fixes (pseudofixes) along the desired path to make the arc. These have to be defined in the FIXES section before using them in the procedure.I find the geographic center of the arc and the radius, makes the definitions easy. You can use the FIX xxxxx COLOCATED syntax to place the fixes at a bearing/distance from the center. I get fancy and calculate the actual lat/lon but that's not necessary.Terry has a fine tutorial at his website planepath.com (in the utilities section).