(3) Q-routes and T-routes outside Alaska.
Q-routes require system performance currently met
by GPS, GPS/WAAS, or DME/DME/IRU RNAV
systems that satisfy the criteria discussed in AC
90-100, U.S. Terminal and En Route Area
Navigation (RNAV) Operations. T-routes require
GPS or GPS/WAAS equipment.

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.

REFERENCE-
AIM, Paragraph 5-3-4 , Airways and Route Systems.

(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).

(c) GPS IFR approach/departure operations
can be conducted when approved avionics systems
are installed and the following requirements are met:
(1) The aircraft is TSO-C145() or TSO-
C146() or TSO-C196() or TSO-C129() in Class A1,
B1, B3, C1, or C3; and
(2) The approach/departure must be retrievable from the current airborne navigation
database in the navigation computer. The system
must be able to retrieve the procedure by name from
the aircraft navigation database. Manual entry of
waypoints using latitude/longitude or place/bearing
is not permitted for approach procedures.
(3) The authorization to fly instrument
approaches/departures with GPS is limited to U.S.
airspace.
(4) The use of GPS in any other airspace
must be expressly authorized by the FAA Administrator.
(5) GPS instrument approach/departure
operations outside the U.S. must be authorized by
the appropriate sovereign authority.
4. Departures and Instrument Departure
Procedures (DPs)
The GPS receiver must be set to terminal (1 NM)
CDI sensitivity and the navigation routes contained in
the database in order to fly published IFR charted
departures and DPs. Terminal RAIM should be
automatically provided by the receiver. (Terminal
RAIM for departure may not be available unless the
waypoints are part of 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

Navigation Aids

5. GPS Instrument Approach Procedures

NOTE-
Overlay approaches do not adhere to the design criteria
described in Paragraph 5-4-5m, 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

1-1-25