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AIM

10/12/17

5−4−22

Arrival Procedures

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

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.