error), if it is available in the approach mode, may
help the pilot remain position oriented in this
situation. Being established on the final approach
course prior to the beginning of the sensitivity change
at 2 NM will help prevent problems in interpreting the
CDI display during ramp down. Therefore, request
ing or accepting vectors which will cause the aircraft
to intercept the final approach course within 2 NM of
the FAWP is not recommended.
(6) When receiving vectors to final, most
receiver operating manuals suggest placing the
receiver in the non-sequencing mode on the FAWP
and manually setting the course. This provides an
extended final approach course in cases where the
aircraft is vectored onto the final approach course
outside of any existing segment which is aligned with
the runway. Assigned altitudes must be maintained
until established on a published segment of the
approach. Required altitudes at waypoints outside the
FAWP or stepdown fixes must be considered.
Calculating the distance to the FAWP may be
required in order to descend at the proper location.
(7) Overriding an automatically selected
sensitivity during an approach will cancel the
approach mode annunciation. If the approach mode
is not armed by 2 NM prior to the FAWP, the approach
mode will not become active at 2 NM prior to the
FAWP, and the equipment will flag. In these
conditions, the RAIM and CDI sensitivity will not
ramp down, and the pilot should not descend to MDA,
but fly to the MAWP and execute a missed approach.
The approach active annunciator and/or the receiver
should be checked to ensure the approach mode is
active prior to the FAWP.
(8) Do not attempt to fly an approach unless
the procedure in the onboard database is current and
identified as "GPS" on the approach chart. The
navigation database may contain information about
non-overlay approach procedures that enhances
position orientation generally by providing a map,
while flying these approaches using conventional
NAVAIDs. This approach information should not be
confused with a GPS overlay approach (see the
receiver operating manual, AFM, or AFM Supple
ment for details on how to identify these procedures
in the navigation database). Flying point to point on
the approach does not assure compliance with the
published approach procedure. The proper RAIM
sensitivity will not be available and the CDI

Navigation Aids

sensitivity will not automatically change to 0.3
NM. Manually setting CDI sensitivity does not
automatically change the RAIM sensitivity on some
receivers. Some existing non-precision approach
procedures cannot be coded for use with GPS and will
not be available as overlays.
(9) Pilots should pay particular attention
to the exact operation of their GPS receivers for
performing holding patterns and in the case of
overlay approaches, operations such as procedure
turns. These procedures may require manual
intervention by the pilot to stop the sequencing of
waypoints by the receiver and to resume automatic
GPS navigation sequencing once the maneuver is
complete. The same waypoint may appear in the route
of flight more than once consecutively (for example,
IAWP, FAWP, MAHWP on a procedure turn). Care
must be exercised to ensure that the receiver is
sequenced to the appropriate waypoint for the
segment of the procedure being flown, especially if
one or more fly-overs are skipped (for example,
FAWP rather than IAWP if the procedure turn is not
flown). The pilot may have to sequence past one or
more fly-overs of the same waypoint in order to start
GPS automatic sequencing at the proper place in the
sequence of waypoints.
(10) Incorrect inputs into the GPS receiver
are especially critical during approaches. In some
cases, an incorrect entry can cause the receiver to
leave the approach mode.
(11) A fix on an overlay approach identi
fied by a DME fix will not be in the waypoint
sequence on the GPS receiver unless there is a
published name assigned to it. When a name is
assigned, the along track distance (ATD) to the
waypoint may be zero rather than the DME stated on
the approach chart. The pilot should be alert for this
on any overlay procedure where the original
approach used DME.
(12) If a visual descent point (VDP) is
published, it will not be included in the sequence of
waypoints. Pilots are expected to use normal piloting
techniques for beginning the visual descent, such as
ATD.
(13) Unnamed stepdown fixes in the final
approach segment may or may not be coded in the
waypoint sequence of the aircraft"s navigation
database and must be identified using ATD.
Stepdown fixes in the final approach segment of

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