In general, waypoint names use the first three letters to
identify the aerodrome, the next letter to identify the compass
quadrant from which the approach is flown, and the final
letter for the approach waypoint. As an example, the
Runway 24 GPS approach for Paraburdoo, WA (YPBO) uses
“PBO” as the first three letters, and “E” as the fourth letter, of
all waypoints. The various waypoints are identified as
follows:
•
The initial approach waypoints (usually a selection of three)
allow flying of the approach without use of a sector entry
procedure. The initial points mark the start of the approach
and are usually designated with “A”, “B” and “C” as the fifth
letter of the waypoint name.
•
The intermediate waypoint achieves alignment with the final
approach course and has “I” as its fifth letter.
•
The final approach waypoint marks the point where the
receiver has completed transition to the approach mode (CDI
scale and RAIM tolerance goes to 0.3nm) and has the “F”
designator.
•
The missed approach waypoint is normally at the runway
threshold and is designated with the letter “M”. The missed
approach mode must be manually selected for the receiver to
give missed approach tracking information. On selection, the
receiver CDI scale and RAIM tolerance reverts to 1.0nm.
•
A missed approach turning waypoint, if required, is designated
with the letter “T”.
•
The missed approach holding waypoint is designated with the
letter “H” and used to provide tracking for the missed
approach.
The exception to this rule is that initial approach fixes may be
given a pronounceable five letter name when they are located
at the terminating waypoint of a STAR.