RNAV (GPS) Approaches
If your airplane has been approved for RNAV (GPS) or RNAV (GNSS) approaches, and if you have been trained, then you are cleared in hot. Right? Not so fast.
I seem to get into this argument with instructors at FlightSafety a lot, so here goes:
They: "We can fly a VOR or NDB approach without GPS in the title using the FMS because the AFM says we can."
That isn't true, here is what the AFM says
I seem to get into this argument with instructors at FlightSafety a lot, so here goes:
They: "We can fly a VOR or NDB approach without GPS in the title using the FMS because the AFM says we can."
That isn't true, here is what the AFM says
A lot of this confusion came from the temporary GPS overlay program which did allow the use of GPS for VOR approaches. But that program is over, the Advisory Circular (AC 90-94) was rescinded in 2009 and the AIM USED TO SAY:
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”).
But it doesn't say that anymore. Now it says you can fly other approaches using a suitable RNAV system provided the underlying navaid is operational and monitored.
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”).
But it doesn't say that anymore. Now it says you can fly other approaches using a suitable RNAV system provided the underlying navaid is operational and monitored.
WGS-84
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.
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:
You cannot fly an RNAV (GPS) approach unless your aircraft database and the approach designers are using the same coordinate system. Chances are your airplane database uses the World Geodetic System of 1984 (WGS-84) so your approaches must also. The rules internationally depend on the country's WGS-84 status and national policy as found in their AIP and Jeppesen State pages. You can also find a more up-to-date list here: http://ww1.jeppesen.com/company/publications/wgs-84.jsp.
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:
- all coordinate data must be referenced to the World Geodetic System — 1984 (WGS-84);
- all surveys must be based upon the International Terrestrial Reference Frame;
- all data must be traceable to their source;
- equipment used for surveys must be adequately calibrated;
You cannot fly an RNAV (GPS) approach unless your aircraft database and the approach designers are using the same coordinate system. Chances are your airplane database uses the World Geodetic System of 1984 (WGS-84) so your approaches must also. The rules internationally depend on the country's WGS-84 status and national policy as found in their AIP and Jeppesen State pages. You can also find a more up-to-date list here: http://ww1.jeppesen.com/company/publications/wgs-84.jsp.
Making Sense of Approach Types: RNAV (GPS)
"GPS" Absent From Title
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.
The "Presque Isle VOR DME RWY 1," for example, cannot be flown using GPS, you must use VOR and DME.
The "Presque Isle VOR DME RWY 1," for example, cannot be flown using GPS, you must use VOR and DME.
Presque Isle, ME VOR DME Rwy 1
"RNAV" Appears in Title
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.
There aren't any examples to show as they have all been phased out.
There aren't any examples to show as they have all been phased out.
"or GPS" Appears in Title
GPS overlay procedures that are based on pre-existing nonprecision 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.”
Avalon, CA VOR or GPS-A
"GPS" Only in Title
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.
Astoria, OR GPS Rwy 8
"RNAV (GPS)" Approaches
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.
Jackson, WY RNAV (GPS) X Rwy 1
New Overlay Procedures
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.
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.
Uses of Suitable RNAV Systems. Subject to the operating requirements, operators may use a suitable RNAV system in the following ways.
NOTE--
NOTE--
- 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.
- Navigate to or from a VOR, TACAN, NDB, or compass locator.
- Hold over a VOR, TACAN, NDB, compass locator, or DME fix.
- Fly an arc based upon DME.
- The allowances described in this section apply even when a facility is identified as required on a procedure (for example, “Note ADF required”).
- These operations do not include lateral navigation on localizer−based courses (including localizer back−course guidance) without reference to raw localizer data.
- 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.
- 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.
- 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.
- 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.
Making Sense of Approach Types: RNAV (GNSS)
GPS is a subset of GNSS. In my opinion you can treat the RNAV (GNSS) as you would an RNAV (GPS), provided your aircraft is equipped and approved. See your AFM to be sure.
If you AFM or POH lists approved procedures, you need to see RNAV (GNSS) on the list or you can't fly them. If your AFM or POH doesn't list any approved procedures at all, well I guess it is open to question.
Commercial operators will need to have RNAV (GNSS) listed as an approved approach type in their operations specifications (C052, or equivalent).
If you AFM or POH lists approved procedures, you need to see RNAV (GNSS) on the list or you can't fly them. If your AFM or POH doesn't list any approved procedures at all, well I guess it is open to question.
Commercial operators will need to have RNAV (GNSS) listed as an approved approach type in their operations specifications (C052, or equivalent).
C052 Approved procedures example
The country in question must be WGS-84 compliant.
You must comply with any additional requirements imposed by the host country, if any, as listed in their Aeronautical Information Publication or the Jeppesen State pages, Requirements and Regulations.
You must comply with any additional requirements imposed by the host country, if any, as listed in their Aeronautical Information Publication or the Jeppesen State pages, Requirements and Regulations.
RNAV (GNSS) Example
Can you fly an RNAV (GNSS) approach in a country not in the country of your aircraft registration or pilot's license? It is, after all, just aRNAV (GPS) approach.
I can't answer that for you, but for me, with an N-Numbered aircraft and a pilot's license issued by the United States Federal Aviation Administration the unequivocally answer is:
It Depends
Here is an example which shows the process on how to answer that question for yourself.
I can't answer that for you, but for me, with an N-Numbered aircraft and a pilot's license issued by the United States Federal Aviation Administration the unequivocally answer is:
It Depends
Here is an example which shows the process on how to answer that question for yourself.
- Is the aircraft qualified to fly a GNSS approach?
- Is the operator allowed to fly a GNSS approach?
- Are the pilots trained to fly a GNSS approach?
- Is the country in which the approach is flown WGS-84 compliant?
- Does the ICAO permit RNAV procedures using GNSS?
- Does the country in which the approach is flown restrict foreign operators from using the approach?
Example: Toluca RNAV (GNSS) Runway 15
The approach looks okay except it says (GNSS) instead of (GPS) and you have heard that we United States registered aircraft aren't allow to fly these. Time for some research.
Toluca, Mexico RNAV (GNSS) Rwy 15
1. Aircraft Qualification
Is the aircraft certified to fly these approaches? The G450 AFM 1-34-30 explicitly mentions RNAV (GNSS) as an approved procedure but makes note that this is not true for operations in non-WGS-84 airspace and may not be true in countries which are partially compliant.
WGS-84 compliance basically means the country in question used latitudes and longitudes that are measured to the same standards as used by the GPS / GNSS satellites themselves.
WGS-84 compliance basically means the country in question used latitudes and longitudes that are measured to the same standards as used by the GPS / GNSS satellites themselves.
Approved approach procedures
2. Operator Qualification
Commercial operators should have RNAV (GNSS) listed in their C052 (or equivalent) Operations Specifications.
C052 Approved procedures example
3. Pilot Qualification
Commercial operators may have a specific training requirement or simply leave it up to the training provider to train all those procedures authorized in the operations specifications.
For the rest of us, there is nothing in 14 CFR 61.58 or 61.157 that says you have to be evaluated on every approach you are qualified to fly.
For the rest of us, there is nothing in 14 CFR 61.58 or 61.157 that says you have to be evaluated on every approach you are qualified to fly.
Flight operations training manual example
4. WGS-84 Compliance
WGS-84 Status Report example
Is the country WGS-84 compliant? The Jeppesen State Pages, National Regulations and Requirements, might have the answer, but quite often are out of date. For an up-to-date listing, consult http://ww1.jeppesen.com/company/publications/wgs-84.jsp. For our Mexican example, we see that Mexico is indeed WGS-84 compliant.
5. ICAO Approval
Aircraft equipped with basic GNSS receivers (either as stand-alone equipment or in a multi-sensor environment) that have been approved by the State of the Operator for departure and non-precision approach operations may use these systems to carry out RNAV procedures provided that before conducting any flight, the following criteria are met:
a) the GNSS equipment is serviceable;
b) the pilot has a current knowledge of how to operate the equipment so as to achieve the optimum level of navigation performance;
c) satellite availability is checked to support the intended operation;
d) an alternate airport with conventional navaids has been selected; and
e) the procedure is retrievable from an airborne navigation database.
a) the GNSS equipment is serviceable;
b) the pilot has a current knowledge of how to operate the equipment so as to achieve the optimum level of navigation performance;
c) satellite availability is checked to support the intended operation;
d) an alternate airport with conventional navaids has been selected; and
e) the procedure is retrievable from an airborne navigation database.
6. Host Nation Exceptions
Nations are required to list their difference with ICAO in their Aeronautical Information Publications (AIP). Very few nations publish their AIPs so we rely on Jeppesen to publish these differences in their State pages, Regulations and Requirements. Very few nations mention RNAV (GNSS) at all and those that do almost always permit its use provided a few restrictions are met.
France Rules and Regulations extract
Australia Rules and Regulations extract
Mexico lists no restrictions at all. We had a specialist from Universal read the Mexican AIP and translate their requirements:
There are still those who say you can't do it unless you have a Mexican tail number, a Mexican pilot's license, and you hablo Espanol. If you have an ILS option you should probably do that. But I think with a little research you can do the RNAV (GNSS).
- The aircraft must have the RNAV equipment authorized by the appropriate governing authorities in the country in which the aircraft is registered in (i.e. FAA).
- The airport must have an authorized system. (As of 21 Jul 2013, only MMTO is authorized in Mexico.).
- The crew must have received RNAV training.
There are still those who say you can't do it unless you have a Mexican tail number, a Mexican pilot's license, and you hablo Espanol. If you have an ILS option you should probably do that. But I think with a little research you can do the RNAV (GNSS).