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AIM 

6/17/21 

established. Obstacle clearance is provided to allow 
a momentary descent below DA while transitioning 
from the final approach to the missed approach. The 
aircraft is expected to follow the missed instructions 
while continuing along the published final approach 
course to at least the published runway threshold 
waypoint or MAP (if not at the threshold) before 
executing any turns. 

(b) 

Minimum Descent Altitude (MDA) has 

been in use for many years, and will continue to be 
used for the LNAV only and circling procedures. 

(c) 

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. 

6. 

The  MINIMA FORMAT will also change 

slightly. 

(a) 

Each line of minima on the RNAV IAP is 

titled to reflect the level of service available; e.g., 
GLS, LPV, LNAV/VNAV, LP, and LNAV. CIR-
CLING minima will also be provided. 

(b) 

The minima title box indicates the nature 

of the minimum altitude for the IAP. For example: 

(1) 

DA  will be published next to the 

minima line title for minimums supporting vertical 
guidance such as for GLS, LPV or LNAV/VNAV. 

(2) 

MDA will be published as the minima 

line on approaches with lateral guidance only, LNAV, 
or LP. Descent below the MDA must meet the 
conditions stated in 14 CFR Section 91.175. 

(3) 

Where two or more systems, such as 

LPV and LNAV/VNAV, share the same minima, each 
line of minima will be displayed separately. 

7. 

Chart Symbology changed slightly to 

include: 

(a)  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. 

(1) 

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. 

(2) 

The stabilized approach may be per-

formed 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. 

(b)  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. 

(c)  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 5

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6). 

(d)  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 

Arrival Procedures 

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