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AIM 

6/17/21 

1. 

The minima lines are: 

(a)  GLS. 

“GLS” is the acronym for GBAS 

Landing System. The U.S. version of GBAS has 
traditionally been referred to as LAAS. The 
worldwide community has adopted GBAS as the 
official term for this type of navigation system. To 
coincide with international terminology, the FAA is 
also adopting the term GBAS to be consistent with the 
international community. This line was originally 
published as a placeholder for both WAAS and LAAS 
minima and marked as N/A since no minima was 
published. As the concepts for GBAS and WAAS 
procedure publication have evolved, GLS will now 
be used only for GBAS minima, which will be on a 
separate approach chart. Most RNAV(GPS) approach 
charts have had the GLS minima line replaced by a 
WAAS LPV line of minima. 

(b)  LPV. 

“LPV” is the acronym for localizer 

performance with vertical guidance. RNAV (GPS) 
approaches to LPV lines of minima take advantage of 
the improved accuracy of WAAS lateral and vertical 
guidance to provide an approach that is very similar 
to a Category I Instrument Landing System (ILS). 
The approach to LPV line of minima is designed for 
angular guidance with increasing sensitivity as the 
aircraft gets closer to the runway. The sensitivities are 
nearly identical to those of the ILS at similar 
distances. This was done intentionally to allow the 
skills required to proficiently fly an ILS to readily 
transfer to flying RNAV (GPS) approaches to the 
LPV line of minima. Just as with an ILS, the LPV has 
vertical guidance and is flown to a DA. Aircraft can 
fly this minima line with a statement in the Aircraft 
Flight Manual that the installed equipment supports 
LPV approaches. This includes Class 3 and 4 
TSO

C146 GPS/WAAS equipment. 

(c)  LNAV/VNAV.

 LNAV/VNAV identifies 

APV minimums developed to accommodate an 
RNAV IAP with vertical guidance, usually provided 
by approach certified Baro

VNAV, but with lateral 

and vertical integrity limits larger than a precision 
approach or LPV. LNAV stands for Lateral 
Navigation; VNAV stands for Vertical Navigation. 
This minima line can be flown by aircraft with a 
statement in the Aircraft Flight Manual that the 
installed equipment supports GPS approaches and 
has an approach

approved barometric VNAV, or if 

the aircraft has been demonstrated to support 
LNAV/VNAV approaches. This includes Class 2, 3 

and 4 TSO

C146 GPS/WAAS equipment. Aircraft 

using LNAV/VNAV minimums will descend to 
landing via an internally generated descent path 
based on satellite or other approach approved VNAV 
systems. Since electronic vertical guidance is 
provided, the minima will be published as a DA. 
Other navigation systems may be specifically 
authorized to use this line of minima. (See Section A, 
Terms/Landing Minima Data, of the U.S. Terminal 
Procedures books.) 

(d)  LP. 

“LP” is the acronym for localizer 

performance. Approaches to LP lines of minima take 
advantage of the improved accuracy of WAAS to 
provide approaches, with lateral guidance and 
angular guidance. Angular guidance does not refer to 
a glideslope angle but rather to the increased lateral 
sensitivity as the aircraft gets closer to the runway, 
similar to localizer approaches. However, the LP line 
of minima is a Minimum Descent Altitude (MDA) 
rather than a DA (H). Procedures with LP lines of 
minima will not be published with another approach 
that contains approved vertical guidance (LNAV/ 
VNAV or LPV). It is possible to have LP and LNAV 
published on the same approach chart but LP will 
only be published if it provides lower minima than an 
LNAV line of minima. LP is not a fail

down mode for 

LPV. LP will only be published if terrain, 
obstructions, or some other reason prevent publishing 
a vertically guided procedure. WAAS avionics may 
provide GNSS

based advisory vertical guidance 

during an approach to an LP line of minima. 
Barometric altimeter information remains the 
primary altitude reference for complying with any 
altitude restrictions. WAAS equipment may not 
support LP, even if it supports LPV, if it was approved 
before TSO

C145b and TSO

C146b. Receivers 

approved under previous TSOs may require an 
upgrade by the manufacturer in order to be used to fly 
to LP minima. Receivers approved for LP must have 
a statement in the approved Flight Manual or 
Supplemental Flight Manual including LP as one of 
the approved approach types. 

(e)  LNAV. 

This minima is for lateral 

navigation only, and the approach minimum altitude 
will be published as a minimum descent altitude 
(MDA). LNAV provides the same level of service as 
the present GPS stand alone approaches. LNAV 
minimums support the following navigation systems: 
WAAS, when the navigation solution will not support 
vertical navigation; and, GPS navigation systems 

Arrival Procedures 

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