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the active flight plan rather than proceeding direct to the first
destination.) Certain segments of a DP may require

some manual intervention by the pilot, especially when radar vectored
to a course or required to intercept a

specific course to a waypoint. The database may not contain all of the
transitions or departures from all runways

and some GPS receivers do not contain DPs in the database.  It is
necessary that helicopter procedures be flown

at 70 knots or less since helicopter departure procedures and missed
approaches use a 20:1 obstacle clearance

surface (OCS), which is double the fixed

-

wing OCS, and turning areas are based on this speed as well.

5.  GPS Instrument Approach Procedures

(a)

GPS overlay approaches are designated non

-

precision instrument approach procedures that pilots are

authorized to fly using GPS avionics. Localizer (LOC), localizer type
directional aid (LDA), and simplified

directional facility (SDF) procedures are not authorized. Overlay
procedures are identified by the "name of

the procedure" and "or GPS" (e.g., VOR/DME or GPS RWY 15) in the title.
Authorized procedures must be

retrievable from a current onboard navigation database. The navigation
database may also enhance position

orientation by displaying a map containing information on conventional
NAVAID approaches. This approach

information should not be confused with a GPS overlay approach (see the
receiver operating manual, AFM,

or AFM Supplement for details on how to identify these approaches in
the navigation database).

NOTE

-

Overlay approaches do not adhere[1] to the design criteria described in
paragraph 5

[2]-

[3]4

[4]-

[5]5m, Area Navigation (RNAV)

Instrument Approach Charts, for stand

-

alone GPS approaches. Overlay approach criteria is based on the
design criteria

used for ground

-

based NAVAID approaches.

(b)

Stand

-

alone approach procedures specifically designed for GPS systems have
replaced many of the

original overlay approaches. All approaches that contain "GPS" in the
title (e.g., "VOR or GPS RWY 24," "GPS

RWY 24," or "RNAV (GPS) RWY 24") can be flown using GPS. GPS

-

equipped aircraft do not need underlying

ground

-

based NAVAIDs or associated aircraft avionics to fly the approach.
Monitoring the underlying approach

with ground

-

based NAVAIDs is suggested when able. Existing overlay approaches may
be requested using the

GPS title; for example, the VOR or GPS RWY 24 may be requested as "GPS
RWY 24." Some GPS procedures

have a Terminal Arrival Area (TAA) with an underlining RNAV approach.

(c)

For flight planning purposes, TSO-C129() and TSO-C196()

-

equipped users (GPS users) whose

navigation systems have fault detection and exclusion (FDE) capability,
who perform a preflight RAIM

prediction for the approach integrity at the airport where the RNAV
(GPS) approach will be flown, and have

proper knowledge and any required training and/or approval to conduct a
GPS-based IAP, may file based on

a GPS

-

based IAP at either the destination or the alternate airport, but not
at both locations. At the alternate

airport, pilots may plan for:

(1)

Lateral navigation (LNAV) or circling minimum descent altitude (MDA);

(2)

LNAV/vertical navigation (LNAV/VNAV) DA, if equipped with and using
approved barometric

vertical navigation (baro-VNAV) equipment;

(3)

RNP 0.3 DA on an RNAV (RNP) IAP, if they are specifically authorized
users using approved

baro-VNAV equipment and the pilot has verified required navigation
performance (RNP) availability through

an approved prediction program.

(d)

If the above conditions cannot be met, any required alternate airport m
ust have an approved

instrument approach procedure other than GPS

-

based that is anticipated to be operational and available at the

estimated time of arrival, and which the aircraft is equipped to fly.

(e)  Procedures for Accomplishing GPS Approaches

(1)

An RNAV (GPS) procedure may be associated with a Terminal Arrival Area
(TAA). The basic

design of the RNAV procedure is the "T" design or a modification of the
"T" (See Paragraph 5-4-5d, Terminal

Arrival Area (TAA), for complete information).

(2)

Pilots cleared by ATC for an RNAV (GPS) approach should fly the full
approach from an Initial

Approach Waypoint (IAWP) or feeder fix. Randomly joining an approach at
an intermediate fix does not assure

terrain clearance.

-

-

Navigation Aids

References

1. file:///media/stevei/plnkx/aspirations/go-faraim/work/src/faraim/faa/aim/98/aim-98.html#0
2. file:///media/stevei/plnkx/aspirations/go-faraim/work/src/faraim/faa/aim/98/aim-98.html#0
3. file:///media/stevei/plnkx/aspirations/go-faraim/work/src/faraim/faa/aim/98/aim-98.html#0
4. file:///media/stevei/plnkx/aspirations/go-faraim/work/src/faraim/faa/aim/98/aim-98.html#0
5. file:///media/stevei/plnkx/aspirations/go-faraim/work/src/faraim/faa/aim/98/aim-98.html#0