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AIM

10/12/17

5

−4−23

Arrival Procedures

which are presently authorized to conduct GPS
approaches.

NOTE

GPS receivers approved for approach operations in
accordance with: AC 20

−138, Airworthiness Approval of

Positioning and Navigation Systems, qualify for this
minima. WAAS navigation equipment must be approved in
accordance with the requirements specified in
TSO

−C145() or TSO−C146() and installed in accordance

with Advisory Circular AC 20

−138.

2.

Other systems may be authorized to utilize

these approaches. See the description in Section A of
the U.S. Terminal Procedures books for details.
Operational approval must also be obtained for
Baro

−VNAV systems to operate to the LNAV/VNAV

minimums. Baro

−VNAV may not be authorized on

some approaches due to other factors, such as no local
altimeter source being available. Baro

−VNAV is not

authorized on LPV procedures. Pilots are directed to
their local Flight Standards District Office (FSDO)
for additional information.

NOTE

RNAV and Baro

−VNAV systems must have a manufacturer

supplied electronic database which must include the
waypoints, altitudes, and vertical data for the procedure to
be flown. The system must be able to retrieve the procedure
by name from the aircraft navigation database, not just as
a manually entered series of waypoints.

3. ILS or RNAV (GPS) charts.

 

(a)

Some RNAV (GPS) charts will also

contain an ILS line of minima to make use of the ILS
precision final in conjunction with the RNAV GPS
capabilities for the portions of the procedure prior to
the final approach segment and for the missed
approach. Obstacle clearance for the portions of the
procedure other than the final approach segment is
still based on GPS criteria.

NOTE

Some GPS receiver installations inhibit GPS navigation
whenever ANY ILS frequency is tuned. Pilots flying
aircraft with receivers installed in this manner must wait
until they are on the intermediate segment of the procedure
prior to the PFAF (PFAF is the active waypoint) to tune the
ILS frequency and must tune the ILS back to a VOR
frequency in order to fly the GPS based missed approach.

(b) Charting

. There are charting differences

between ILS, RNAV (GPS), and GLS approaches.

(1)

The LAAS procedure is titled “GLS

RWY XX” on the approach chart.

(2)

The VDB provides information to the

airborne receiver where the guidance is synthesized.

(3)

The LAAS procedure is identified by a

four alpha

−numeric character field referred to as the

RPI or approach ID and is similar to the IDENT
feature of the ILS.

(4)

The RPI is charted.

(5)

Most RNAV(GPS) approach charts

have had the GLS (NA) minima line replaced by an
LPV line of minima.

(6)

Since the concepts for LAAS and

WAAS procedure publication have evolved, GLS
will now be used only for LAAS minima, which will
be on a separate approach chart.

4. Required Navigation Performance (RNP).

(a)

Pilots are advised to refer to the

“TERMS/LANDING MINIMUMS DATA” (Sec-
tion A) of the U.S. Government Terminal Procedures
books for aircraft approach eligibility requirements
by specific RNP level requirements.

(b)

Some aircraft have RNP approval in their

AFM without a GPS sensor. The lowest level of
sensors that the FAA will support for RNP service is
DME/DME. However, necessary DME signal may
not be available at the airport of intended operations.
For those locations having an RNAV chart published
with LNAV/VNAV minimums, a procedure note may
be provided such as “DME/DME RNP

−0.3 NA.”

This means that RNP aircraft dependent on
DME/DME to achieve RNP

−0.3 are not authorized to

conduct this approach. Where DME facility
availability is a factor, the note may read “DME/DME
RNP

−0.3 Authorized; ABC and XYZ Required.”

This means that ABC and XYZ facilities have been
determined by flight inspection to be required in the
navigation solution to assure RNP

−0.3. VOR/DME

updating must not be used for approach procedures.

5. Chart Terminology.

(a)

Decision Altitude (DA) replaces the

familiar term Decision Height (DH). DA conforms to
the international convention where altitudes relate to
MSL and heights relate to AGL. DA will eventually
be published for other types of instrument approach
procedures with vertical guidance, as well. DA
indicates to the pilot that the published descent profile
is flown to the DA (MSL), where a missed approach
will be initiated if visual references for landing are not

2/28/19

AIM