CHANGES TO NAVAID IDENTIFICATION IN DATABASE

NDB NAVAID IDENTIFICATION CHANGES 
Sept 12, 1996

A fax has recently been sent from Jeppesen to their customers describing
a change in how Non-Directional Beacons (NDBs) will be loaded in the
database. This change will make NDBs more accessible and it will
standardize the way the pilot chooses characters to call up a navaid in
the FMC.

Few notes:
You may reproduce this article for training purposes only. You may not
reproduce it for commercial publication without the author's permission.
I'd like to thank those who assisted but must remain nameless. 
This article uses the Smiths (737 installation) and Honeywell (757/767
installation) as examples. This information may not fit the Fokker, MD,
or Airbus systems. Nor does this article pertain to nav database
providers such as Racal and SwissAir; I have not talked to them.
If you can contribute information for these systems, please send me the
description and we'll update the article.



ARINC Specification 424, Nav System Data Base is the industry standard.

OLD METHOD:
Two NDBs in the same ICAO region (usually a country) with the same
identifier could not be kept in the NDB file.
To the pilot, this means that it can be accessed by entering the
identifier, either one, two, or three letters, into the FMC.
If a second NDB had the same identifier or derived name such as "NB"
after the full name, it was listed in the wpt file, which may require
typing in the full name, not the identifier. Duplicate NDBs were not
always coded as waypoints based on their full names. They were often
coded as the ident + NB; some computer systems actually add the NB
suffix to the name. It gets quite complicated and further exploration is
not necessary for this article.

Example:
Bogata has an NDB named ROMEO; identifier is R. It is in the database as
an NDB and called up as R.

Cali has an NDB named ROZO; identifier is R. It is in the old database
as a wpt and called up as ROZO. It was not filed as an NDB in the old
database; it could not be called up by entering R.


NEW METHOD:
NDBs will be listed in the NDB file. They can be called up using their
identifier, just like VORTACs.


TARGET DATE

As for the ROZO waypoint, it has been deleted in the cycle 9610 database
effective 12 Sept.
Both R NDBs at Bogata and Cali are now referenced by their idents.
Jeppesen is targeting further adjustments in cycle 9611. More NDBs will
be converted/added to the NDB file which were previously handled as
waypoints. 
There are a certain number of these which will not be converted due to a
lack of terminal facilities which to associate them with, and a list of
these will be published by Jeppesen at a later date.

Jeppesen publishes a list of NDBs which are currently duplicated within
an ICAO region, and thus not resident in the NDB file. The majority of
this list will be cancelled after the 9611 database load. Jeppesen plans
on publishing a short list of those NDBs which they are unable to
convert for reasons stated above.

NOTE:
When a fix is duplicated, the pilot must pick the desired fix from the
SELECT DESIRED WPT page. In certain cases there will be up to two pages,
six fixes to a page, so the lat/lon must be examined carefully. In fact,
you're now going to see ROMEO and ROZO on the SELECT DESIRED WPT page -
just one degree difference. If you have the habit of automatically
selecting the first one on the page, break this habit.
Differences exist is the way fixes are listed on the SELECT DESIRED WPT
page in the 737 (Smiths) and the 757/767 (Honeywell) FMCs. Refer to your
FMS publication.

Bill Bulfer
bbulfer@firstnethou.com