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Approach Procedures
Operations
Naming Conventions
When a name must be provided for an otherwise unnamed waypoint,
the naming will use the ARINC-424, chapter 7 specified convention
whenever possible. There are a few types of waypoints, DME arc
waypoints greater than 26 nm from the reference and single character
NDB idents, which are not adequately addressed by the ARINC-424
specification. Most of these names are intuitive after you understand a
few of the rules. The entire ARINC naming conventions are not
included here, but the following guidelines will probably explain the
names you see assigned to these waypoints.
First, the exceptions:
DME arc or DME-distance/bearing waypoints that are greater than 26
miles from their reference point. The standard ARINC convention for
DME arc or DME-distance/bearing (sometimes called Rho-Theta)
waypoints is to use 'D' followed by the bearing from the waypoint,
followed by an Alpha character from A to Z corresponding to the
number of miles, from 1 to 26, rounded to the nearest whole mile. A
waypoint on the BKE VOR 272 radial at 25 nm would then be named
D272Y as is the IAF in the Baker, Oregon approach example above.
When the distance is greater than 26 miles, such as for the Topeka, KS
VOR DME RWY 3 approach, the waypoint is named by using the first
two characters of the reference navaid ID, followed by the bearing
from the navaid. The IAF at the Topeka VOR, TOP, located on the 231
radial at 31 nm is then named TO231. The IAF on the TOP 176 radial at
31 nm is named TO176.
Canada and some South American countries have multiple NDBs with
the same ident. When these are in the same ICAO region, they can't
both be in the data. When this happens, one airport which uses a Golf
NDB, "G," would have the waypoint named "G." The next airport that
uses a "G" NDB in the approach waypoints would have a waypoint
named with the 1 letter ident and 'NB' for NDB appended to it;
therefore, it would appear in the database as "GNB" at the second
airport.
Standard Naming Conventions
In general, the following codes are used to correspond to a waypoint
type. When they are associated with an approach to a specific runway,
232
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