It is an elegant idea but that isn't the point. Your FMS uses these codes to represent various points around the globe so you need to know how to decode the code. Once you've got it, it is pretty easy but there are pitfalls:
- Going from one quadrant of the world to the next you have to change your expectations and look up the new pattern.
- Not every major lat/long has a code, if you are unfamiliar with the region you need to expand the coded waypoint to make sure it means what you think it means.
- Do not get into the trap of reading the code for your position report; very few of the codes translate into a valid position report format.
- There are times your CPDLC will rewrite the nifty, compact codes into non-descript labels; you may not want this.
Most of this comes from bits and pieces gleamed from http://www.arinc.com/.
What is it?
ARINC 424 or ARINC 424 Navigation System Data Base Standard is an international standard file format for aircraft navigation data maintained by Airlines Electronic Engineering Committee and published by Aeronautical Radio, Inc. The ARINC 424 specifications are not a database, but a "standard for the preparation and transmission of data for assembly of airborne navigation system data bases".
The Shorthand Explained
Many FMS navigation databases include the ARINC 424 Shorthand System for latitude and longitude points that simplifies lat/long entry:
- The shorthand always uses one letter and four digits, the letter used places the waypoint in its quadrant:
- N .. N latitude W longitude
- E .. N latitude E longitude
- S .. S latitude E longitude
- W .. S latitude W longitude
- If the longitude is less than 100 degrees, the letter is put at the end. Otherwise, the letter is put where the “1” would normally appear.
- 5030N .. 50N 030W
- 50N30 .. 50N 130W
- 5030E .. 50N 030E
- If the resulting input yields a “waypoint not found” error, the selected point might not be included in the shorthand database and must be entered manually.