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AIM

4/20/23

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Navigation Aids

(b)

Conduct GPS domestic, en route, and terminal IFR operations only when approved avionics

systems are installed. Pilots may use GPS via TSO

C129() authorized for Class A1, B1, B3, C1, or C3 operations

GPS via TSO-C196(); or GPS/WAAS with either TSO-C145() or TSO-C146(). When using TSO-C129() or
TSO-C196() receivers, the avionics necessary to receive all of the ground

based facilities appropriate for the

route to the destination airport and any required alternate airport must be installed and operational.
Ground

based facilities necessary for these routes must be operational.

(1)

GPS en route IFR operations may be conducted in Alaska outside the operational service volume

of ground

based navigation aids when a TSO

C145() or TSO

C146() GPS/wide area augmentation system

(WAAS) system is installed and operating. WAAS is the U.S. version of a satellite-based augmentation system
(SBAS).

[a]

In Alaska, aircraft may operate on GNSS Q-routes with GPS (TSO-C129 () or TSO-C196 ())

equipment while the aircraft remains in Air Traffic Control (ATC) radar surveillance or with GPS/WAAS
(TSO-C145 () or TSO-C146 ()) which does not require ATC radar surveillance.

[b]

In Alaska, aircraft may only operate on GNSS T-routes with GPS/WAAS (TSO-C145 () or

TSO-C146 ()) equipment.

(2)

Ground

based navigation equipment is not required to be installed and operating for en route IFR

operations when using GPS/WAAS navigation systems. All operators should ensure that an alternate means of
navigation is available in the unlikely event the GPS/WAAS navigation system becomes inoperative.

(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.

REFERENCE

AIM, Para 5

3

4, Airways and Route Systems.

(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 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