9/5/24 

AIM 

(e) 

The naming of multiple approaches of the same type to the same runway is also changing. Multiple 

approaches with the same guidance will be annotated with an alphabetical suffix beginning at the end of the 

alphabet and working backwards for subsequent procedures (e.g., ILS Z RWY 28, ILS Y RWY 28, etc.). The 

existing annotations such as ILS 2 RWY 28 or Silver ILS RWY 28 will be phased out and replaced with the new 

designation. The Cat II and Cat III designations are used to differentiate between multiple ILSs to the same 

runway unless there are multiples of the same type. 

(f) 

RNAV (GPS) approaches to LNAV, LP, LNAV/VNAV and LPV lines of minima using WAAS and 

RNAV (GPS) approaches to LNAV and LNAV/VNAV lines of minima using GPS are charted as RNAV (GPS) 

RWY (Number) (e.g., RNAV (GPS) RWY 21). 

(g) 

Performance

−

Based Navigation (PBN) Box. As charts are updated, a procedure’s PBN requirements 

and conventional equipment requirements will be prominently displayed in separate, standardized notes boxes. 

For procedures with PBN elements, the PBN box will contain the procedure’s navigation specification(s); and, 

if required: specific sensors or infrastructure needed for the navigation solution, any additional or advanced 

functional requirements, the minimum Required Navigation Performance (RNP) value, and any amplifying 

remarks. Items listed in this PBN box are REQUIRED for the procedure’s PBN elements. For example, an ILS 

with an RNAV missed approach would require a specific capability to fly the missed approach portion of the 

procedure. That required capability will be listed in the PBN box. The separate Equipment Requirements box 

will list ground

−

based equipment requirements. On procedures with both PBN elements and equipment 

requirements, the PBN requirements box will be listed first. The publication of these notes will continue 

incrementally until all charts have been amended to comply with the new standard. 

4. 

Approach minimums are based on the local altimeter setting for that airport, unless annotated otherwise; 

e.g., Oklahoma City/Will Rogers World approaches are based on having a Will Rogers World altimeter setting. 

When a different altimeter source is required, or more than one source is authorized, it will be annotated on the 

approach chart; e.g., use Sidney altimeter setting, if not received, use Scottsbluff altimeter setting. Approach 

minimums may be raised when a nonlocal altimeter source is authorized. When more than one altimeter source 

is authorized, and the minima are different, they will be shown by separate lines in the approach minima box or 

a note; e.g., use Manhattan altimeter setting; when not available use Salina altimeter setting and increase all 

MDAs 40 feet. When the altimeter must be obtained from a source other than air traffic a note will indicate the 

source; e.g., Obtain local altimeter setting on CTAF. When the altimeter setting(s) on which the approach is based 

is not available, the approach is not authorized. Baro

−

VNAV must be flown using the local altimeter setting only. 

Where no local altimeter is available, the LNAV/VNAV line will still be published for use by WAAS receivers 

with a note that Baro

−

VNAV is not authorized. When a local and at least one other altimeter setting source is 

authorized and the local altimeter is not available Baro

−

VNAV is not authorized; however, the LNAV/VNAV 

minima can still be used by WAAS receivers using the alternate altimeter setting source. 

NOTE

−

 

Barometric Vertical Navigation (baro

−

VNAV).  An RNAV system function which uses barometric altitude information from 

the aircraft’s altimeter to compute and present a vertical guidance path to the pilot. The specified vertical path is computed 

as a geometric path, typically computed between two waypoints or an angle based computation from a single waypoint. 

Further guidance may be found in Advisory Circular 90

−

105. 

5. 

A pilot adhering to the altitudes, flight paths, and weather minimums depicted on the IAP chart or vectors 

and altitudes issued by the radar controller, is assured of terrain and obstruction clearance and runway or airport 

alignment during approach for landing. 

6. 

IAPs are designed to provide an IFR descent from the en route environment to a point where a safe landing 

can be made. They are prescribed and approved by appropriate civil or military authority to ensure a safe descent 

during instrument flight conditions at a specific airport. It is important that pilots understand these procedures 

and their use prior to attempting to fly instrument approaches. 

7. 

TERPS criteria are provided for the following types of instrument approach procedures: 

Arrival Procedures 

5

−

4

−

7