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course to at least the published runway threshold
waypoint or MAP (if not at the threshold) before
executing any turns.
12.11.5.2 Minimum Descent Altitude (MDA) has
been in use for many years, and will continue to be
used for the LNAV only and circling procedures.
3114 J FUELBY 08
ENR 1.5−38 AIP
15 MAR 07 United States of America
Nineteenth Edition Federal Aviation Administration
12.11.5.3 Threshold Crossing Height (TCH) has
been traditionally used in “precision” approaches as
the height of the glide slope above threshold. With
publication of LNAV/VNAV minimums and RNAV
descent angles, including graphically depicted
descent profiles, TCH also applies to the height of the
“descent angle,” or glidepath, at the threshold. Unless
otherwise required for larger type aircraft which may
be using the IAP, the typical TCH is 30 to 50 feet.
12.11.6 The MINIMA FORMAT will also change
slightly.
12.11.6.1 Each line of minima on the RNAV IAP is
titled to reflect the level of service available;
e.g., GLS, LPV, LNAV/VNAV, and LNAV. CIRCLING
minima will also be provided.
12.11.6.2 The minima title box indicates the nature
of the minimum altitude for the IAP. For example:
a) DA will be published next to the minima line
title for minimums supporting vertical guidance such
as for GLS, LPV or LNAV/VNAV.
b) MDA will be published where the minima line
was designed to support aircraft with only lateral
guidance available, such as LNAV. Descent below the
MDA, including during the missed approach, is not
authorized unless the visual conditions stated in
14 CFR Section 91.175 exist.
c) Where two or more systems, such as LPV and
LNAV/VNAV, share the same minima, each line of
minima will be displayed separately.
12.11.7 Chart Symbology changed slightly to
include:
12.11.7.1 Descent Profile. The published descent
profile and a graphical depiction of the vertical path
to the runway will be shown. Graphical depiction of
the RNAV vertical guidance will differ from the
traditional depiction of an ILS glide slope (feather)
through the use of a shorter vertical track beginning
at the decision altitude.
a) It is FAA policy to design IAPs with minimum
altitudes established at fixes/waypoints to achieve
optimum stabilized (constant rate) descents within
each procedure segment. This design can enhance the
safety of the operations and contribute toward
reduction in the occurrence of controlled flight into
terrain (CFIT) accidents. Additionally, the National
Transportation Safety Board (NTSB) recently
emphasized that pilots could benefit from publication
of the appropriate IAP descent angle for a stabilized
descent on final approach. The RNAV IAP format
includes the descent angle to the hundredth of a
degree; e.g., 3.00 degrees. The angle will be provided
in the graphically depicted descent profile.
b) The stabilized approach may be performed by
reference to vertical navigation information provided
by WAAS or LNAV/VNAV systems; or for
LNAV−only systems, by the pilot determining the
appropriate aircraft attitude/groundspeed combination
to attain a constant rate descent which best
emulates the published angle. To aid the pilot, U.S.
Government Terminal Procedures Publication charts
publish an expanded Rate of Descent Table on the
inside of the back hard cover for use in planning and
executing precision descents under known or
approximate groundspeed conditions.
12.11.7.2 Visual Descent Point (VDP). A VDP
will be published on most RNAV IAPs. VDPs apply
only to aircraft utilizing LP or LNAV minima, not
LPV or LNAV/VNAV minimums.
12.11.7.3 Missed Approach Symbology. In order
to make missed approach guidance more readily
understood, a method has been developed to display
missed approach guidance in the profile view through
the use of quick reference icons. Due to limited space
in the profile area, only four or fewer icons can be
shown. However, the icons may not provide
representation of the entire missed approach
procedure. The entire set of textual missed approach
instructions are provided at the top of the approach
chart in the pilot briefing. (See FIG ENR 1.5−20.)
12.11.7.4 Waypoints. All RNAV or GPS stand−
alone IAPs are flown using data pertaining to the
particular IAP obtained from an onboard database,
including the sequence of all WPs used for the
approach and missed approach, except that step down
waypoints may not be included in some TSO−C−129
receiver databases. Included in the database, in most
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