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AIM

10/12/17

1−2−9

Performance−Based Navigation (PBN) and Area Navigation (RNAV)

identified as not authorized (“NA”) without exception by
a NOTAM.  For example, an operator may not use a RNAV
system to navigate on a procedure affected by an expired or
unsatisfactory flight inspection, or a procedure that is
based upon a recently decommissioned NAVAID.

4. Pilots may not substitute for the NAVAID (for example,
a VOR or NDB) providing lateral guidance for the final
approach segment. This restriction does not refer to
instrument approach procedures with “or GPS” in the title
when using GPS or WAAS. These allowances do not apply
to procedures that are identified as not authorized (NA)
without exception by a NOTAM, as other conditions may
still exist and result in a procedure not being available. For
example, these allowances do not apply to a procedure
associated with an expired or unsatisfactory flight
inspection, or is based upon a recently decommissioned
NAVAID.

5. Use of a suitable RNAV system as a means to navigate
on the final approach segment of an instrument approach
procedure based on a VOR, TACAN or NDB signal, is
allowable. The underlying NAVAID must be operational
and the NAVAID monitored for final segment course
alignment. 

6. For the purpose of paragraph c, “VOR” includes VOR,
VOR/DME, and VORTAC facilities and “compass
locator” includes locator outer marker and locator middle
marker.

d. Alternate Airport Considerations. For the

purposes of flight planning, any required alternate

airport must have an available instrument approach

procedure that does not require the use of GPS. This

restriction includes conducting a conventional

approach at the alternate airport using a substitute

means of navigation that is based upon the use of

GPS. For example, these restrictions would apply

when planning to use GPS equipment as a substitute

means of navigation for an out−of−service VOR that

supports an ILS missed approach procedure at an

alternate airport. In this case, some other approach

not reliant upon the use of GPS must be available.

This restriction does not apply to RNAV systems

using TSO−C145/−C146 WAAS equipment. For

further WAAS guidance, see paragraph 1−1−18.

1. 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 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 applicable

alternate airport weather minimums using:

(a) Lateral navigation (LNAV) or circling

minimum descent altitude (MDA);

(b) LNAV/vertical navigation (LNAV/

VNAV) DA, if equipped with and using approved

barometric vertical navigation (baro-VNAV) equip-

ment;

(c) 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.

2. If the above conditions cannot be met, any

required alternate airport must have an approved

instrument approach procedure other than GPS that is

anticipated to be operational and available at the

estimated time of arrival, and which the aircraft is

equipped to fly.

3. This restriction does not apply to

TSO-C145() and TSO-C146() equipped users

(WAAS users). For further WAAS guidance, see

paragraph 1−1−18.

1−2−4. Pilots and Air Traffic Controllers

Recognizing Interference or Spoofing

a. Pilots need to maintain position awareness

while navigating. This awareness may be facilitated

by keeping relevant ground−based, legacy naviga-

tional aids tuned and available. By utilizing this

practice, situational awareness is promoted and

guards against significant pilot delay in recognizing

the onset  of GPS interference. Pilots may find

cross−checks of other airborne systems (for example,

DME/DME/IRU or VOR) useful to mitigate this

otherwise undetected hazard.

REFERENCE−

AIM Paragraph 1−1−17, Global Positioning System (GPS)

AIM Paragraph 1−1−18, Wide Area Augmentation System (WAAS)

b. During preflight planning, pilots should be

particularly alert for NOTAMs which could affect

navigation (GPS or WAAS) along their route of

flight, such as Department of Defense electronic

signal tests with GPS.

REFERENCE−

AIM Paragraph 1−1−17, Global Positioning System (GPS)

AIM Paragraph 1−1−18, Wide Area Augmentation System (WAAS)

2/28/19

AIM