RNAV(GPS)

The title of the remaining GPS overlay procedures has been revised on the approach chart to “or GPS” (e.g., VOR or GPS RWY 24). Therefore, all the approaches that can be used by GPS now contain “GPS” in the title (e.g., “VOR or GPS RWY 24,” “GPS RWY 24,” or “RNAV (GPS) RWY 24”).

Source: Aeronautical Information Manual 15 Dec 2015 ¶1-1-19.g.

The navigation data published in the State AIP for the routes and supporting navigation aids must meet the requirements of Annex 15 — Aeronautical Information Services. All routes must be based upon WGS-84 coordinates.

Source: ICAO Doc 9613 ¶1.2.5.2

Navigation data may originate from survey observations, from equipment specifications/settings or from the airspace and procedure design process. Whatever the source, the generation and the subsequent processing of the data must take account of the following:

1. all coordinate data must be referenced to the World Geodetic System — 1984 (WGS-84);
2. all surveys must be based upon the International Terrestrial Reference Frame;
3. all data must be traceable to their source;
4. equipment used for surveys must be adequately calibrated;

Source: ICAO Doc 9613 ¶3.4

The approach is named based on the NAVAIDs required for the final approach. If the term "GPS" is not in the title, you cannot use GPS to fly the approach.

Source: FAA-H-8261-1, Instrument Procedures Handbook, Pg 5-8

The term "RNAV" allows pilots to use various means of area navigation, including but not requiring GPS. They enable specific VOR/DME RNAV equipment to create waypoints on the final approach path by virtually “moving” the VOR a specific DME distance along a charted radial.

Source: FAA-H-8261-1, Instrument Procedures Handbook, Pg 5-10

GPS overlay procedures that are based on pre-existing non-precision approaches contain the wording “or GPS” in the title. The title “VOR/DME or GPS A” denotes that throughout the GPS approach, the underlying ground-based NAVAIDs are not required to be operational and associated aircraft avionics need not be installed, operational, turned on, or monitored. The procedure can be used as a GPS approach or as a traditional VOR/DME approach and may be requested using “GPS” or “VOR/DME.”

Source: FAA-H-8261-1, Instrument Procedures Handbook, Pg 5-10

Stand-alone GPS procedures are not based on any other procedures, but they may replace other procedures. The naming convention used for stand-alone GPS approaches is “GPS RWY XX.” The coding for the approach in the database does not accommodate multisensor FMSs because these procedures are designed only to accommodate aircraft using GPS equipment.

Source: FAA-H-8261-1, Instrument Procedures Handbook, Pg 5-10

RNAV (GPS) approach procedures have been developed in an effort to accommodate all RNAV systems, including multi-sensor FMSs. RNAV (GPS) IAPs are authorized as stand-alone approaches for aircraft equipped with RNAV systems that contain an airborne navigation database and are certified for instrument approaches. GPS systems require that the coding for a GPS approach activate the Receiver Autonomous Integrity Monitoring (RAIM) function, which is not a requirement for other RNAV equipment. The RNAV procedures are coded with both the identifier for a GPS approach and the identifier for an RNAV approach so that both systems can be used.

Source: FAA-H-8261-1, Instrument Procedures Handbook, Pg 5-10

a. 1−2−3. Use of Suitable Area Navigation (RNAV) Systems on Conventional Procedures and Routes

This change allows for the use of a suitable RNAV system as a means to navigate on the final approach segment of an instrument approach procedure (IAP) based on a VOR, TACAN, or NDB signal. The underlying NAVAID must be operational and monitored for the final segment course alignment.

Source: AIM 26 May 2016, Explanation of Changes.

Uses of Suitable RNAV Systems. Subject to the operating requirements, operators may use a suitable RNAV system in the following ways.

1. Determine aircraft position relative to, or distance from a VOR (see NOTE 5 below), TACAN, NDB, compass locator, DME fix; or a named fix defined by a VOR radial, TACAN course, NDB bearing, or compass locator bearing intersecting a VOR or localizer course.
2. Navigate to or from a VOR, TACAN, NDB, or compass locator.
3. Hold over a VOR, TACAN, NDB, compass locator, or DME fix.
4. Fly an arc based upon DME.

NOTE—

1. The allowances described in this section apply even when a facility is identified as required on a procedure (for example, “Note ADF required”).
2. These operations do not include lateral navigation on localizer−based courses (including localizer back−course guidance) without reference to raw localizer data.
3. Unless otherwise specified, a suitable RNAV system cannot be used for navigation on procedures that are identified as not authorized (“NA”) without exception by a NOTAM. For example, an operator may not use a RNAV system to navigate on a procedure affected by an expired or unsatisfactory flight inspection, or a procedure that is based upon a recently decommissioned NAVAID.
4. Pilots may not substitute for the NAVAID (for example, a VOR or NDB) providing lateral guidance for the final approach segment. This restriction does not refer to instrument approach procedures with “or GPS” in the title when using GPS or WAAS. These allowances do not apply to procedures that are identified as not authorized (NA) without exception by a NOTAM, as other conditions may still exist and result in a procedure not being available. For example, these allowances do not apply to a procedure associated with an expired or unsatisfactory flight inspection, or is based upon a recently decommissioned NAVAID.
5. Use of a suitable RNAV system as a means to navigate on the final approach segment of an instrument approach procedure based on a VOR, TACAN or NDB signal, is allowable. The underlying NAVAID must be operational and the NAVAID monitored for final segment course alignment.
6. For the purpose of paragraph c, “VOR” includes VOR, VOR/DME, and VORTAC facilities and “compass locator” includes locator outer marker and locator middle marker.

Source: AIM 26 May 2016, ¶1-2-3.c.