3. A different WAAS-based line of minima,
called Localizer Performance (LP) is being added in
locations where the terrain or obstructions do not
allow publication of vertically guided LPV minima.
LP takes advantage of the angular lateral guidance
and smaller position errors provided by WAAS to
provide a lateral only procedure similar to an ILS
Localizer. LP procedures may provide lower minima
than a LNAV procedure due to the narrower obstacle
clearance surface.

NOTE-
WAAS receivers certified prior to TSO-C145b and
TSO-C146b, even if they have LPV capability, do not
contain LP capability unless the receiver has been
upgraded. Receivers capable of flying LP procedures must
contain a statement in the Aircraft Flight Manual (AFM),
AFM Supplement, or Approved Supplemental Flight
Manual stating that the receiver has LP capability, as well
as the capability for the other WAAS and GPS approach
procedure types.
4. WAAS provides a level of service that
supports all phases of flight, including RNAV (GPS)
approaches to LNAV, LP, LNAV/VNAV, and LPV
lines of minima, within system coverage. Some
locations close to the edge of the coverage may have
a lower availability of vertical guidance.

c. General Requirements

1. WAAS avionics must be certified in
accordance with Technical Standard Order (TSO)
TSO-C145(), Airborne Navigation Sensors Using
the (GPS) Augmented by the Wide Area Augmenta-
tion System (WAAS); or TSO-C146(), Stand-Alone
Airborne Navigation Equipment Using the Global
Positioning System (GPS) Augmented by the Wide
Area Augmentation System (WAAS), and installed in
accordance with Advisory Circular (AC) 20-138(),
Airworthiness Approval of Positioning and Naviga-
tion Systems.

2. GPS/WAAS operation must be conducted in
accordance with the FAA-approved aircraft flight
manual (AFM) and flight manual supplements. Flight
manual supplements will state the level of approach
procedure that the receiver supports. IFR approved
WAAS receivers support all GPS only operations as
long as lateral capability at the appropriate level is
functional. WAAS monitors both GPS and WAAS

satellites and provides integrity.

3. GPS/WAAS equipment is inherently capable
of supporting oceanic and remote operations if the

operator obtains a fault detection and exclusion
(FDE) prediction program.
4. Air carrier and commercial operators must
meet the appropriate provisions of their approved
operations specifications.

5. Prior to GPS/WAAS IFR operation, the pilot
must review appropriate Notices to Airmen (NOT-
AMs) and aeronautical information. This
information is available on request from a Flight
Service Station. The FAA will provide NOTAMs to
advise pilots of the status of the WAAS and level of
service available.

(a) The term MAY NOT BE AVBL is used in
conjunction with WAAS NOTAMs and indicates that
due to ionospheric conditions, lateral guidance may
still be available when vertical guidance is
unavailable. Under certain conditions, both lateral
and vertical guidance may be unavailable. This
NOTAM language is an advisory to pilots indicating
the expected level of WAAS service (LNAV/VNAV,
LPV, LP) may not be available.
EXAMPLE-
!FDC FDC NAV WAAS VNAV/LPV/LP MINIMA MAY
NOT BE AVBL 1306111330-1306141930EST
or
!FDC FDC NAV WAAS VNAV/LPV MINIMA NOT AVBL,
WAAS LP MINIMA MAY NOT BE AVBL
1306021200-1306031200EST

WAAS MAY NOT BE AVBL NOTAMs are
predictive in nature and published for flight planning
purposes. Upon commencing an approach at
locations NOTAMed WAAS MAY NOT BE AVBL,
if the WAAS avionics indicate LNAV/VNAV or LPV
service is available, then vertical guidance may be
used to complete the approach using the displayed
level of service. Should an outage occur during the
approach, reversion to LNAV minima or an alternate
instrument approach procedure may be required.
When GPS testing NOTAMS are published and
testing is actually occurring, Air Traffic Control will
advise pilots requesting or cleared for a GPS or
RNAV (GPS) approach that GPS may not be
available and request intentions. If pilots have
reported GPS anomalies, Air Traffic Control will
request the pilot's intentions and/or clear the pilot for
an alternate approach, if available and operational.

(b) WAAS area-wide NOTAMs are origin-

ated when WAAS assets are out of service and impact
the service area. Area-wide WAAS NOT AVAIL-
ABLE (AVBL) NOTAMs indicate loss or