Aeronautical Information Manual (AIM), page 342

Index   341 -- Page 342 -- 343


LOC minimums will be annotated with the NAVAID
required (e.g., "DME Required" or "RADAR
Required"). During the transition period, ILS
approaches will still exist without the annotation.

(d) Many ILS approaches having minima
based on RVR are eligible for a landing minimum of
RVR 1800. Some of these approaches are to runways
that have touchdown zone and centerline lights. For
many runways that do not have touchdown and
centerline lights, it is still possible to allow a landing
minimum of RVR 1800. For these runways, the
normal ILS minimum of RVR 2400 can be annotated
with a single or double asterisk or the dagger symbol
"†"; for example "** 696/24 200 (200/1/2)." A note
is included on the chart stating "**RVR 1800
authorized with use of FD or AP or HUD to DA." The
pilot must use the flight director, or autopilot with an
approved approach coupler, or head up display to
decision altitude or to the initiation of a missed
approach. In the interest of safety, single pilot
operators should not fly approaches to 1800 RVR
minimums on runways without touchdown and
centerline lights using only a flight director, unless
accompanied by the use of an autopilot with an
approach coupler.

(e) The naming of multiple approaches of the
same type to the same runway is also changing.
Multiple approaches with the same guidance will be
annotated with an alphabetical suffix beginning at the
end of the alphabet and working backwards for
subsequent procedures (e.g., ILS Z RWY 28, ILS Y
RWY 28, etc.). The existing annotations such as
ILS 2 RWY 28 or Silver ILS RWY 28 will be phased
out and replaced with the new designation. The Cat II
and Cat III designations are used to differentiate

between multiple ILSs to the same runway unless

there are multiples of the same type.

(f) RNAV (GPS) approaches to LNAV, LP,
LNAV/VNAV and LPV lines of minima using WAAS
and RNAV (GPS) approaches to LNAV and
LNAV/VNAV lines of minima using GPS are charted
as RNAV (GPS) RWY (Number) (e.g., RNAV (GPS)
RWY 21). VOR/DME RNAV approaches will
continue to be identified as VOR/DME RNAV RWY
(Number) (e.g., VOR/DME RNAV RWY 21).
VOR/DME RNAV procedures which can be flown by
GPS will be annotated with "or GPS"
(e.g., VOR/DME RNAV or GPS RWY 31).

4. Approach minimums are based on the local
altimeter setting for that airport, unless annotated
otherwise; e.g., Oklahoma City/Will Rogers World
approaches are based on having a Will Rogers World
altimeter setting. When a different altimeter source is
required, or more than one source is authorized, it will
be annotated on the approach chart; e.g., use Sidney
altimeter setting, if not received, use Scottsbluff
altimeter setting. Approach minimums may be raised
when a nonlocal altimeter source is authorized. When
more than one altimeter source is authorized, and the
minima are different, they will be shown by separate
lines in the approach minima box or a note; e.g., use
Manhattan altimeter setting; when not available use
Salina altimeter setting and increase all MDAs
40 feet. When the altimeter must be obtained from a
source other than air traffic a note will indicate the
source; e.g., Obtain local altimeter setting on CTAF.
When the altimeter setting(s) on which the approach
is based is not available, the approach is not
authorized. Baro-VNAV must be flown using the
local altimeter setting only. Where no local altimeter
is available, the LNAV/VNAV line will still be
published for use by WAAS receivers with a note that
Baro-VNAV is not authorized. When a local and at
least one other altimeter setting source is authorized
and the local altimeter is not available Baro-VNAV
is not authorized; however, the LNAV/VNAV
minima can still be used by WAAS receivers using the
alternate altimeter setting source.
Barometric Vertical Navigation (baro-VNAV). An RNAV
system function which uses barometric altitude informa-
tion from the aircraft's altimeter to compute and present
a vertical guidance path to the pilot. The specified vertical
path is computed as a geometric path, typically computed
between two waypoints or an angle based computation
from a single waypoint. Further guidance may be found in

Advisory Circular 90-105.

5. A pilot adhering to the altitudes, flight paths,
and weather minimums depicted on the IAP chart or
vectors and altitudes issued by the radar controller, is
assured of terrain and obstruction clearance and
runway or airport alignment during approach for
6. IAPs are designed to provide an IFR descent
from the en route environment to a point where a safe
landing can be made. They are prescribed and
approved by appropriate civil or military authority to
ensure a safe descent during instrument flight
conditions at a specific airport. It is important that

5-4-6 Arrival Procedures

Page 342 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

Index   341 -- Page 342 -- 343