Draft AC 90-119 Performance-Based Navigation Operations

An important new Advisory Circular 90-119 Performance-Based Navigation Operations was released for comment in May 2021 and is still in the review and coordination phase at FAA.

At the April 24, 2023 Aeronautical Charting Meeting, the FAA announced that a revised draft of AC 90-119 will be released for another round of public comment, probably in June-July 2023.

You can find the first draft PDF in my Aviation Documents folder here.

You can read my detailed initial comments to FAA here (PDF).

This advisory circular (AC) replaces and consolidates several ACs…and provides guidance for operators using Performance-based Navigation (PBN) in the United States, in oceanic and remote continental airspace, and in foreign countries that adopt International Civil Aviation Organization (ICAO) PBN standards.

The draft AC includes updates to FAA policy in some key areas, and it will replace several existing guidance documents, including:

  • AC 90-100A CHG 2, U.S. Terminal and En Route Area Navigation (RNAV) Operations, dated April 14, 2015;
  • AC 90-105A, Approval Guidance for RNP Operations and Barometric Vertical Navigation in the U.S. National Airspace System and in Oceanic and Remote Continental Airspace, dated March 7, 2016;
  • AC 90-107, Guidance for Localizer Performance with Vertical Guidance and Localizer Performance without Vertical Guidance Approach Operations in the U.S. National Airspace System, dated February 11, 2011; and
  • AC 90-108 CHG 1, Use of Suitable Area Navigation (RNAV) Systems on Conventional Routes and Procedures, dated April 21, 2015.

The language in this AC also affects sections of the AIM; FAA handbooks such as the Instrument Flying Handbook and Instrument Procedures Handbook; and Airmen Certification Standards that include instrument tasks.

Key Updates

Here are some of the key updates to FAA guidance and policy in the new AC. Detailed discussion of each item follows.

  • Use of suitable RNAV systems on conventional routes and procedures, which clarifies how you can use an IFR-approved GPS on all types of IFR procedures, including those that use localizer courses, until you reach the final approach segment.
  • Expanded definition and clarification of the term RNP APCH, which many pilots confuse with RNP AR APCH. FAA adds RNP APCH notes to approaches with RNAV (GPS) in the title and does not plan to adopt current ICAO conventions for naming PBN procedures (for background, see this post here at BruceAir). More details on this topic appear below.
  • Updated definition of precision approach, which now explicitly includes all RNAV (GPS) approaches with LPV minimums. The AC also aligns FAA terminology with the ICAO definitions for procedures that include 2D (lateral navigation) and 3D (lateral and vertical navigation).

Use of Suitable RNAV Systems on Conventional Routes and Procedures

For general aviation pilots who use IFR-approved GPS and WAAS avionics, the draft AC clarifies a key issue, the use of RNAV (i.e., GPS and WAAS) while flying routes and procedures based on navaids. In particular, Chapter 11 describes specific situations in which pilots can use RNAV as an alternate means of navigation or as a substitute for navaids, and the document clarifies when you can use GPS to navigate along localizer courses outside the final approach segment.

(I recently gave a webinar for the American Bonanza Society on this topic. You can watch that presentation here and read more about the topic here.)

The draft AC provides the following updated definitions: Alternate Means of Navigation. The pilot’s use of a suitable RNAV system to navigate on a conventional route or procedure without monitoring the operational NAVAID(s) defining the route or procedure. “Alternate means” applies to a situation where the pilot has options or a choice, and uses the suitable RNAV system primarily for convenience. Substitute Means of Navigation. The pilot’s use of a suitable RNAV system to navigate on a conventional route or procedure in an aircraft with inoperative or not-installed conventional navigation equipment and/or when conventional NAVAIDs are out of service. “Substitution” applies to a situation where the NAVAID or the aircraft equipment are inoperative or unavailable (i.e., the pilot cannot use or monitor the conventional NAVAID). Suitable RNAV System. Per § 1.1, an RNAV system is suitable when it (1) is installed for IFR operations, and (2) meets the navigation performance criteria required by ATC for the route or procedure to be flown. Put simply, suitable RNAV systems are those that meet the criteria identified in this AC for RNAV operations.

Section 11.4.2 Authorized Uses of Suitable RNAV Systems describes specific situations in which you can use GPS to complement or substitute for ground-based navaids.

The most significant update is item 6 (reinforced by paragraph, which clarifies that you can use GPS to navigate all legs of any conventional approach procedure, including procedures based on a localizer, until you reach final approach segment:

1. Determine aircraft position relative to, or distance from, a conventional NAVAID, DME fix, or named fix based on a conventional NAVAID.

2. Navigate to or from any conventional NAVAID or fix, via direct or a defined course.

3. Hold over any conventional NAVAID or DME fix.

4. Fly a published arc based upon DME.

5. Fly a route, comprised of charted airways, fixes, and/or NAVAIDs.

6. Navigate to the FAS of a conventional IAP.

7. Navigate the lateral course of the FAS on an IAP based on a VOR, Tactical Air Navigation System (TACAN), or Non-Directional Beacon (NDB) signal. The aircraft equipment and underlying NAVAID must be operational and monitored for FAS course alignment. The underlying NAVAID remains the primary source of navigation for the FAS course and should be used for course alignment if the RNAV system track differs from the underlying NAVAID course.

Items 1-2 also mean that you can use RNAV to fly departures and arrivals based on conventional navaids.

Item 6 is backed up by additional paragraphs: On Unusable or Not Authorized (NA) Procedures. Pilots may not fly any portion of a conventional route or procedure identified (by chart annotation or NOTAM) as unusable or not authorized (“NA”).

Note: Pilots should take particular care when loading routes by name or title, especially routes defined solely by conventional NAVAIDs. Conventional routes designated as “unusable” by chart notation or NOTAM are unusable by any user. Pilots should not file for, and ATC should not use, the unusable route title or name in the IFR clearance. This does not preclude the use of direct clearances to usable waypoints along or across a charted route designated as “unusable.” [For more background on this issue, see Unusable Airways, Routes, and Segments here at BruceAir.] As Sole Means of Navigation on Conventional FAS. Pilots may not use RNAV as the sole means of navigation to fly the final approach course on a conventional instrument approach. To Navigate a Localizer (LOC) Final Approach Course. Pilots may not use RNAV to fly a FAS defined by an LOC signal.

Together, these sections mean that you can use an IFR-approved GPS to fly departures; airways; arrivals; feeder routes; track a VOR radial or localizer course to a course reversal or HILPT; fly DME arcs; fly holds, including holds based on DME fixes; and to fly the legs of missed approach procedures based on navaids, including localizers.

Paragraph As Sole Means of Navigation on Conventional FAS emphasizes that you cannot use GPS for lateral guidance along the final approach segment of a VOR or NDB approach unless the navaid is operational and you can monitor the course on a bearing pointer or CDI. This paragraph aligns with previous guidance in the AIM and AFM supplements, as I’ve noted in several posts here at BruceAir.


Paragraph 12.3 RNP APCH Overview provides background on the use of the note RNP APCH, which now appears on many charts.

This note is one way that FAA attempts to align its naming conventions for PBN approaches with updated ICAO standards (for background, see FAA InFO16020). As the AC explains:

In the United States, RNP APCH applies to all approach applications based on Global Positioning System (GPS), normally titled “RNAV (GPS)” or with “or GPS” in the title. These procedures provide operators one or more lines of minima (i.e., LNAV, LNAV/VNAV, LPV, or LP)…The RNP APCH NavSpec is intended to encompass all segments of the terminal approach operation: initial, intermediate, final, and missed approach…Charts for RNP APCH procedures will prominently display a standardized PBN Notes Box containing the procedure’s requirements including NavSpec(s) and, if needed, any required sensors or additional functionality (e.g., RF capability), as well as any minimum RNP value required for the procedure, and applicable remarks.

In other words, in the U.S., GPS-based approaches are titled RNAV (GPS) RWY xx. These approaches also include a RNP APCH note to confirm that they require the equipment needed to fly to the RNP terminal and final approach standards (i.e., RNP 1 and RNP 0.3 for LNAV minimums to an MDA or LPV, LNAV/VNAV to a DA, or LP standards for lateral guidance to an MDA).

RNP APCH is not the same as the authorization required to comply with the RNP AR APCH standard. In the U.S. approaches that require the RNP AR APCH standard are titled RNAV (RNP) RWY xx.

As the draft AC notes:

This AC does not apply to Required Navigation Performance Authorization Required Approach (RNP AR APCH) approaches, titled “RNAV (RNP)” (ICAO: RNP RWY xx (AR)). Guidance for RNP AR operations is in AC 90-101( ), Approval Guidance for RNP Procedures with AR.

Definition of Precision Approach

The draft AC updates the definition of precision approach, which now explicitly includes all RNAV (GPS) approaches with LPV minimums. The AC also aligns FAA terminology with the ICAO definitions for procedures that include 2D (lateral navigation) and 3D (lateral and vertical navigation).

In the past, precision approach applied only to procedures based on ground facilities that provide a glideslope or other approved vertical guidance to a DA–viz., an ILS or PAR. That obsolete definition required the creation of a new term, APV (approaches with vertical guidance), for RNAV procedures that offer approved vertical guidance to LPV or LNAV/VNAV decision altitude minimums.

Today, ICAO has updated its definition of precision approach by describing procedures that include approved vertical guidance to a DA, so-called 3D navigation. ICAO also describes so-called 2D approaches to MDAs.

With that change in mind, the new AC explains precision approaches (PA) and nonprecision approaches (NPA) that use GPS: NPA Operations. These two-dimensional (2D) operations use GPS-derived lateral guidance from the RNP system. The procedure provides obstruction clearance as long as the pilots strictly adhere to the published minimum altitudes along the approach course, primarily by reference to the barometric altimeter. These 2D procedures typically have LNAV lines of minima to a minimum descent altitude (MDA). PA Operations. These 3D operations use either ground-based, GPS-derived, and/or integrated electronic vertical guidance from the RNP system to enable lateral and vertical navigation to decision altitude (DA)/decision heights (DH) at or below 250 feet above ground level (AGL) (depending on the presence of obstacles). Typically, these are shown as LPV or LNAV/VNAV (and ILS/GLS) DA/DHs.

This section of the AC also notes that:

Note 2: Some approach procedures that contain both precision and nonprecision features are internationally designated as “Approaches with Vertical Guidance (APV).” These 3D approach procedures use GPS or SBAS to generate integrated electronic vertical and lateral guidance from the RNP system. These procedures typically have LNAV/VNAV lines of minima to DA/DH as low as 251 feet AGL. In the United States, all procedures to a LPV DA (regardless of height above touchdown (HAT)) are considered 3D precision operations. [Emphasis added]

This change should help reduce confusion about when IFR students and applicants for instrument ratings can use RNAV (GPS) approaches with LPV minimums to accomplish requirements for practicing and demonstrating precision approaches on practical tests.

Other Sections

The AC includes updated guidance in several other areas, beyond technical requirements for approval and use of RNAV systems.

For example, paragraph Extract Procedures by Name notes that:

Pilots should extract PBN procedures by name from the onboard navigation database and ensure the extracted procedures match the charted procedures.

Note 1: Pilots operating aircraft with some early-model legacy RNAV navigators may not be able to extract certain PBN departure and arrival procedures by name from the navigation database. In these aircraft, pilots may load the departure or arrival procedures by extracting the individual fixes defining the procedures from the navigation database and loading them into the flight plan for their aircraft’s RNAV system. When this is necessary, pilots should confirm the resulting flight plan content matches the charted PBN procedure.

Note 2: Pilots are also cautioned that some procedures, even if extracted by name from the database, may not contain every segment, turn point, or conditional waypoint, or may contain “computer navigation fixes (CNF)” not shown on the procedure. It is always the pilot’s responsibility to ensure the aircraft’s flightpath conforms to the ATC clearance.

Paragraph Extract PBN Routes in Their Entirety cautions that:

Pilots should extract the PBN routes from the navigation database whenever possible rather than loading the route by stringing individual fixes defining the route in sequence.

Note 1: This does not preclude a pilot’s use of a legacy RNAV navigator that cannot auto-load a PBN route into the navigator’s flight plan. A pilot may load a PBN route by extracting the individual fixes defining the route from the onboard navigation database and loading into the flight plan, fix by fix. When this is necessary, pilots should confirm the resulting flight plan route entries match the charted routes.

Note 2: Caution is warranted when loading routes into the RNAV system for convenience, especially conventional routes defined by ground NAVAIDs. Routes designated as “unusable” by chart notation or NOTAM are unusable by any user. Pilots should not file for, and ATC should not use, the unusable route title or name in the IFR clearance. This does not preclude the use of “direct to” clearances to usable waypoints along a charted route designated as “unusable.”

Paragraph Creating or Altering Waypoints also warns that:

For any published (i.e., charted) PBN routes or procedures, pilots may only use waypoints downloaded from the aircraft navigation database. Pilots may not create waypoints (e.g., by using latitude/longitude coordinates, place/bearing, or any other means) for use on published PBN routes or procedures. Pilots also may not change any parameters of waypoints downloaded from the navigation database (e.g., changing a flyover waypoint to a flyby waypoint).

Paragraph Cross-Check Flight Plan Against ATC Clearance recommends that:

Pilots should cross-check the navigation system’s flight plan against their ATC clearance and the charted routes and procedures. Both the flight plan’s textual display and the aircraft’s electronic moving map display (when available) can aid in this cross-check. When required by NOTAM or by the aircraft’s operating manual and SOP, pilots should confirm exclusion of specific ground-based navigation aids. If at any time during these cross-checks, a pilot doubts the validity of the route or procedure they extracted from the navigation database, they should not attempt to execute the route or procedure.

Note: Pilots may notice a slight difference between the navigation information portrayed on the chart and their primary navigation display. Differences of up to 5 degrees may result from avionics’ application of magnetic variation. These differences are acceptable.

Paragraph 3.6.10 and others in that section explain equipment required notes on PBN procedures. I won’t repeat all those details here. You can find background at Equipment Required Notes on IFR Procedure Charts here at BruceAir. I’ll update that post when I can distill the current FAA guidance as described in the new AC.

Finally, section 3.7 Training offers detailed guidance on the steps pilots should take to ensure that they understand how to use RNAV systems. A list appears in paragraph 3.7.3. Many of these items are also covered in existing industry guidance, such as the free Garmin GTN 750 Sample Training Syllabus (PDF).

The Final Approach “Fix” on an ILS

Consider the ILS RWY 26 at Lewiston, ID (KLWS). This approach is a “pure” ILS; it doesn’t offer an “or LOC” option.

Here’s a question that came up recently during a presentation that I gave to a group of IFR pilots:

“Where’s the final approach fix?”

The profile view does not include the familiar “Maltese cross” that marks the FAF on charts for procedures that include minimums for both a full ILS (a precision approach with a glideslope) and a localizer-only, nonprecision approach to an MDA, as on the ILS RWY 20 at KPWT.

But because the chart for KLWS is only for a precision approach, it doesn’t have a charted “final approach fix.”

Sometimes an approach has different FAFs for variations of the same procedure. For example, the profile view for ILS or LOC RWY 08 at KCLM marks the beginning of the final approach segment for the ILS with the lightning bolt at OCUVI. But if you’re flying the LOC-only procedure, the FAF is at ELWHA, marked by the Maltese cross, another 3.3 nm along the final approach course and 1000 ft lower.

AIM 5−4−5. Instrument Approach Procedure (IAP) Charts includes a note that explains the situation:

The ILS glide slope is intended to be intercepted at the published glide slope intercept altitude. This point marks the PFAF [precision final approach fix] and is depicted by the ”lightning bolt” symbol on U.S. Government charts. Intercepting the glide slope at this altitude marks the beginning of the final approach segment and ensures required obstacle clearance during descent from the glide slope intercept altitude to the lowest published decision altitude for the approach.

The Aeronautical Chart User’s Guide also explains:

Non-Precision Approaches
On non-precision approaches, the final segment begins at the Final Approach Fix (FAF) which is identified with the Maltese cross symbol. When no FAF is depicted, the final approach point is the point at which the aircraft is established inbound on the final approach course. Stepdown fixes may also be provided between the FAF and the airport for authorizing a lower minimum descent angle (MDA) and are depicted with the fix or facility name and a dashed line. On non-precision only approach procedures, the approach track descends to the MDA or VDP point, thence horizontally to the missed approach point.

The ACG offers the following additional distinction:

Precision Approaches
On precision approaches, the glideslope (GS) intercept altitude is illustrated by a zigzag line and an altitude. This is the minimum altitude for GS interception after completion of the procedure turn. Precision approach profiles also depict the GS angle of descent, threshold crossing height (TCH) and GS altitude at the outer marker (OM) or designated fix.

The plan and profile views for the KLWS approach may further confuse matters because they include a computer navigation fix (CNF); in this case (CFLSK). The Pilot/Controller Glossary explains CNF thus:

COMPUTER NAVIGATION FIX (CNF)- A Computer Navigation Fix is a point defined by a latitude/longitude coordinate and is required to support Performance-Based Navigation (PBN) operations. A five-letter identifier denoting a CNF can be found next to an “x” on en route charts and on some approach charts. Eventually, all CNFs will be labeled and begin with the letters “CF” followed by three consonants (e.g., ‘CFWBG’). CNFs are not recognized by ATC, are not contained in ATC fix or automation databases, and are not used for ATC purposes. Pilots should not use CNFs for point-to-point navigation (e.g., proceed direct), filing a flight plan, or in aircraft/ATC communications… (REFER to AIM 1-1-17b5(i)(2), Global Positioning System (GPS). [See below for a more detailed explanation.]

Back to AIM 5-4-5. If you’re flying an ILS, make sure you observe any altitude restrictions outside the published GS intercept altitude. The AIM cautions that:

Interception and tracking of the glide slope prior to the published glide slope interception altitude does not necessarily ensure that minimum, maximum, and/or mandatory altitudes published for any preceding fixes will be complied with during the descent. If the pilot chooses to track the glide slope prior to the glide slope interception altitude, they remain responsible for complying with published altitudes for any preceding stepdown fixes encountered during the subsequent descent.

More about CNFs from AIM 1-1-17b5(i)(2):

A Computer Navigation Fix (CNF) is also a point defined by a latitude/longitude coordinateand is required to support Performance−Based Navigation (PBN) operations. The GPS receiver uses CNFs in conjunction with waypoints to navigate from point to point. However, CNFs are not recognized by ATC. ATC does not maintain CNFs in their database and they do not use CNFs for any air traffic control purpose. CNFs may or may not be charted on FAA aeronautical navigation products, are listed in the chart legends, and are for advisory purposes only. Pilots are not to use CNFs for point to point navigation (proceed direct), filing a flight plan, or in aircraft/ATC communications. CNFs that do appear on aeronautical charts allow pilots increased situational awareness by identifying points in the aircraft database route of flight with points on the aeronautical chart. CNFs are random five-letter identifiers, not pronounceable like waypoints and placed in parenthesis. Eventually, all CNFs will begin with the letters “CF” followed by three consonants (for example, CFWBG). This five-letter identifier will be found next to an “x” on enroute charts and possibly on an approach chart. On instrument approach procedures (charts) in the terminal procedures publication, CNFs may represent unnamed DME fixes, beginning and ending points of DME arcs, and sensor (ground-based signal i.e., VOR, NDB, ILS) final approach fixes on GPS overlay approaches. These CNFs provide the GPS with points on the procedure that allow the overlay approach to mirror the ground-based sensor approach. These points should only be used by the GPS system for navigation and should not be used by pilots for any other purpose on the approach. The CNF concept has not been adopted or recognized by the International Civil Aviation Organization (ICAO).

Note that a modern GPS-based navigator like the Garmin GTN 750 includes the CNF fix CFLSK in the flight plan when you load the ILS RWY 26. And it conveniently labels it as the FAF; that fix corresponds to the GS intercept altitude and marks the beginning of the final approach segment.