RNAV instrument Approach Charts

To avoid unnecessary duplication and proliferation of
approach charts approach minimums for unaugmented
GPS, Wide Area Augmentation System (WAAS), Local
Area Augmentation System (LAAS), will be published
on the same approach chart as lateral navigation/vertical
navigation (LNAV/VNAV'). Other types of equipment may
be authorized to conduct the approach based on the minima
notes in the front of the TPP approach chart books. Approach
charts titled "RNAV RWY XX" may be used by aircraft
with navigation systems that meet the required navigational
performance (RNP) values for each segment of the approach.
[Figure 8-24]

The chart may contain as many as four lines of approach
minimums: global landing system (GLS), WAAS and LAAS,
LNAV/VNAV, LNAV, and circling. LNAV/VNAV is an
instrument approach with lateral and vertical guidance with
integrity limits similar to barometric vertical navigation
(BARO VNAV).

RNAV procedures that incorporate a final approach step-down
fix may be published without on a separate
chart also titled RNAV. During a transition period when GPS
procedures are undergoing revision to anew title, both RNAV
and GPS approach charts and formats will be published. ATC
clearance for the RNAV procedure will authorize a properly
certificated pilot to utilize any landing minimums for which
the aircraft is certified.

Chart terminology will change slightly to support the new
procedure types:

1. DA replaces the term DH. DA conforms to the
international convention where altitudes relate to
MSL and heights relate to AGL. DA will eventually
be published for other types of IAPs with vertical
guidance, as well, DA indicates to the pilot that the
published descent profile is flown to the DA (MSL),
where a missed approach will be initiated if visual
references for landing are not 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 approach 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.

2. MDA will continue to be used only for the LNAV and
circling procedures.

3. Threshold crossing height (TCH) has been traditionally
used in precision approaches as the height of the GS
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 glide
path, at the threshold. Unless otherwise required for
larger type aircraft, which may be using the IAP, the
typical TCH will be 30 to 50 feet.

The minima format changes slightly:
1. Each line of minima on the RNAV IAP will be titled
to reflect the RNAV system applicable (e.g., GLS,
LNAV/VNAV, and LNAV). Circling minima will
also be provided.

2. The minima title box will also indicate the nature of
the minimum altitude for the IAP. For example: DA
will be published next to the minima line title for
minimums supporting vertical guidance, and MDA
will he published where the minima line supports only
lateral guidance. During an approach where an MDA
is used, descent below MDA is not authorized.

3. Where two or more systems share the same minima,
each line of minima will be displayed separately.

For more information concerning government charts, the
NACG can be contacted by telephone, or via their Internet
address at:

National Aeronautical Charting Group
Telephone 800-626-3677
http:/naco.faa.gov/