Is there a syntax/grammar guide for the contents of the files in the SIDSTAR folder? I'd like to modify some and need to know more about the correct usage of keywords etc.

No, there is no Syntax file, but if you look hard enough, you can usually figure out the simple things like SIDs an STARs. Approaches are harder, but all follow the same lanuage. An airport like KATL, KJFK, or KBOS will usually have all the keywords you need. Frankly, it is a very relaxed format like "At or Below" instead of some code.To edit runway data in the NavData folder, it is a little stranger. To edit location, you need to convert XX" XX' XX.XXX coordinates into decimal format. For runway data- 09000092, 09000 is the length in feet, 092 is the heading.Capitalization matters. ALL ENTRYS ARE DONE IN CAP LOCK. No lower case at all. I learned that the hard way. EDIT: Wanted to get that out first. Below is all the keywords I know of.-------------------------------END___ - The identifier to end a section.FIX _____- The prefix to all fix identifiers in the FIXES section, SIDs and STARs.FIX _____ AT OR ABOVE ____ - Cross the fix at or above altitude.FIX _____ AT OR BELOW ____ - Cross the fix at or below altitude.FIXES - The section where the coordinates of all the fixes in the SIDs or STARs go.HDG ___ UNTIL ____ - On a procedure, this means the heading the aircraft will fly until it reaches a certian altitude.LATLON - The prefix for all Latitude and Longitude coordinates.RNW - The Section where all runway names are listed for the airport.RNW ___ - The prefix to the name of the runway. No space between in the approach section.SIDS - The section where all SIDs are entered, using fixes listed in the FIXES section.STARS - The section where all STARs are entered, using fixes listed in the FIXES section.---------------------------------How to build a SIDType in SID. On the same line, type the abbreviated name of the SID. Then enter in all the fixes that are the same for all aircaft on that procedure. On the next line, enter the runways that are availible for that SID, and the directions from the runway to the first waypoint on the first row. If there are any transitions, enter them after the runway section, and the directions from the end of the last fix on row 1, including the transition waypoint.STARs are just about the same.

Edited January 8, 201115 yr by yos233

Terry at Planepath wrote a full guide to it, available here:http://www.planepath.com/html/pmdg_utilities.html

Terry at Planepath wrote a full guide to it, available here:http://www.planepath..._utilities.html

Fine. Show me up. :(