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.

FAA Proposes Cuts to Circling Approach Minimums

The FAA has announced the early stages of plan to evaluate and then cut the number of circling minimums published for instrument approaches.

The FAA published its final criteria to guide the identification and selection of circling procedures that can be considered for cancellation on June 28, 2018. You can read the notice in the Federal Register here.

According to a notice in the Federal Register on October 6, 2017:

In early 2015, the FAA requested the RTCA’s Tactical Operations Committee (TOC) with providing feedback and recommendations on criteria and processes for cancelling instrument flight procedures. Among the many recommendations provided by the TOC were criteria on how to identify circling procedures that would qualify as candidates for cancellation. As of the beginning of 2017, there are approximately 12,000 IAPs in publication, and there were nearly 10,600 circling lines of minima. Circling procedures account for approximately one-third of all lines of minima in the NAS.

In its continued effort to right-size the NAS through optimization and elimination of redundant and unnecessary IAPs, the FAA proposes the following criteria to guide the identification and selection of appropriate circling procedures to be considered for cancellation…

Proposed Policy

All circling procedures will continue to be reviewed through the established IAP periodic review process.As part of that review process, the FAA is proposing that each circling procedure would be evaluated against the following questions:

—Is this the only IAP at the airport?

—Is this procedure a designated MON airport procedure?

—If multiple IAPs serve a single runway end, is this the lowest circling minima for that runway? Note: If the RNAV circling minima is not the lowest, but is within 50′ of the lowest, the FAA would give the RNAV preference.

—Would cancellation result in removal of circling minima from all conventional NAVAID procedures at an airport? Note: If circling minima exists for multiple Conventional NAVAID procedures, preference would be to retain ILS circling minima.

—Would cancellation result in all circling minima being removed from all airports within 20 NMs?

—Will removal eliminate lowest landing minima to an individual runway?

The following questions are applicable only to circling-only procedures:

—Does this circling-only procedure exist because of high terrain or an obstacle that makes a straight-in procedure unfeasible or which would result in the straight-in minimums being higher than the circling minima?

—Is this circling-only procedure (1) at an airport where not all runway ends have a straight-in IAP, and (2) does it have a Final Approach Course not aligned within 45 degrees of a runway which has a straight-in IAP?

Further consideration for cancellation under this policy would be terminated if any of the aforementioned questions are answered in the affirmative. If all questions are answered in the negative, the procedure would be processed as described in the following paragraph.

Changes to Vectors-to-Final in Garmin GTN System 6.x

Garmin has released updated system software (version 6.11) for the GTN series of navigators. The software includes several new features. One of the changes, at least for day-to-day operations for typical general aviation pilots, involves the behavior of the vectors-to-final option (VTF) available when loading an approach.

To learn about and practice using the new features in GTN system 6.x, download the latest version of the free GTN 750 PC Trainer Lite from Garmin. The download includes updated manuals (PDFs) for the GTN series avionics that describe the new features in version 6.x.

The updated Pilot’s Guide for the new system software notes that “all waypoints along the final approach course, including waypoints before the FAF, are included in the flight plan.”

As I noted in Avoiding the Vectors-to-Final Scramble, current versions of the system software for Garmin GNS and GTN units remove all fixes except the FAF and the MAP when you choose VTF:

When you load an approach into your IFR GPS box and choose Vectors-to-Final, the computer typically erases all fixes except the FAF and the MAP, making the snazzy moving map far less useful as an aide to situational awareness. Vectors-to-Final also may lead to a frenzy of knob turning and button pushing if ATC unexpectedly clears you to an IAF or IF instead of setting you up on a heading to intercept the magic magenta extended centerline that Vectors-to-Final draws on your screen.

A note in AIM 5-4-6 Approach Clearance recognizes this issue:

Selection of “Vectors-to-Final” or “Vectors” option for an instrument approach may prevent approach fixes located outside of the FAF from being loaded into an RNAV system. Therefore, the selection of these options is discouraged due to increased workload for pilots to reprogram the navigation system. (AIM 5-4-6)

For that reason, like many instructors, I’ve long recommended against using VTF, especially because ATC can clear an RNAV-capable aircraft direct to an IF or to a fix between the IF and the FAF on any approach (again, see AIM 5-4-6).

For more information, see also Flying Instrument Approaches without Activating the Approach here at my blog.

The change in behavior in GTN units updated to system 6.x may change that recommendation, at least when flying some approaches.

Example: Flying the New VTF

Consider the RNAV (GPS) Y RWY 16R approach at Paine Field (KPAE) north of Seattle, home of the Boeing wide-body aircraft factory that produces the 747, 767, 777, and 787 models. It’s a typical RNAV approach.

If you fly the approach with the current system software for a Garmin GNS or GTN navigator, selecting the VTF option removes all of the fixes except for ITIPE (the FAF) and RW16R (the MAP). The map shows a magenta line extending from the MAP, through the FAF, and out along the final approach course north of the runway. If ATC clears you to EYWOK (an IF/IAF), you must reload the procedure and choose EYWOK as the transition (or ask for a new clearance).

If you choose VTF in an updated GTN navigator, however, the new system software includes all of the fixes along the final approach course, from EYWOK to the MAP at the runway threshold. The FAF, in this case ITIPE, becomes the active waypoint in your flight plan.

And the map shows a magenta line extending from ITIPE out to EYWOK, providing a reference as ATC vectors you to intercept the final approach course.

At this point, I’m still waiting for Garmin to release the new GTN system software and have it installed on my GTN 750. But my tests with the Garmin training software suggest that VTF may become a useful feature when flying some approaches.

If you’re flying with current system software or with a GNS-series unit such as GNS 530 or GNS 430, however, you should follow the recommendation in the AIM and in Avoiding the Vectors-to-Final Scramble to help you stay ahead of the airplane—and your avionics–when flying approaches.

For more information, see also Flying Instrument Approaches without Activating the Approach here at my blog.

FAA Publishes List of Instrument Approaches Set for Cancellation

FAA has published the latest list of 736 VOR and NDB approaches that it wants to cancel. You can download a Microsoft Excel worksheet that includes all of the procedures here.

According to the April 13, 2015 announcement in the Federal Register:

This action proposes to remove certain redundant or underutilized ground-based non-directional beacon and very high frequency, omnidirectional radio range Standard Instrument Approach Procedures based on the criteria established by the FAA’s Policy for Discontinuance of Certain Instrument Approach Procedures.

The announcement offers additional details as background:

On June 27, 2014, the FAA published a policy establishing criteria for cancelling instrument approach procedures (79 FR 36576). Cancelling certain ground-based non-directional beacon (NDB), and very high frequency (VHF), omnidirectional radio range (VOR) SIAPs is one integral part of right-sizing the quantity and type of procedures in the National Airspace System (NAS). As new technology facilitates the introduction of area navigation (RNAV) instrument approach procedures, the number of procedures available in the National Airspace System has nearly doubled over the past decade. The complexity and cost to the FAA of maintaining the existing ground based navigational infrastructure while expanding the new RNAV capability is not sustainable. Therefore, the FAA is proposing the following list of SIAPs for cancellation based on the criteria established in the Policy.

The proposal is open for comments until May 28, 2015.

You can find details about the current inventory of instrument approaches and related procedures at the Instrument Flight Procedures (IFP) Inventory Summary website.

To learn more about specific procedures and procedures in development, visit the Instrument Flight Procedures Information Gateway.

Database Currency for IFR Operations

Most instrument-rated pilots now fly with GPS-based navigation equipment (according to AOPA, at least 78 percent of its members rely on GPS as their primary navigation tool).

To use an IFR-approved GPS when operating IFR, the unit’s database must be current or you must verify the accuracy of the data.

For more details, see note 4 in AIM 1-2-3: Use of Suitable Area Navigation (RNAV) Systems on Conventional Procedures and Routes and AC 90-108.

Keeping a typical GPS unit up-to-date usually involves downloading fresh data to a card every 28 days.

Of course, the effective dates of databases don’t always fall conveniently between trips, and FAA has outlined procedures to help pilots ensure that the data in GPS avionics matches the key information on current charts, especially instrument approach plates.

You must also review either the AFM or the AFM Supplement for the avionics installed in your aircraft. For example, the latest AFM Supplement (190-01007-A2_08) for the Garmin GTN series (750, 650, etc.) notes:

2.8 Navigation Database
GPS/SBAS based IFR enroute, oceanic, and terminal navigation is prohibited unless the flight crew verifies and uses a valid, compatible, and current navigation database or verifies each waypoint for accuracy by reference to current approved data.

“GPS”, “or GPS”, and “RNAV (GPS)” instrument approaches using the Garmin navigation system are prohibited unless the flight crew verifies and uses the current navigation database. GPS based instrument approaches must be flown in accordance with an approved instrument approach procedure that is loaded from the navigation database…

If the navigation database cycle will change during flight, the flight crew must ensure the accuracy of navigation data, including suitability of navigation facilities used to define the routes and procedures for flight. If an amended chart affecting navigation data is published for the procedure, the database must not be used to conduct the procedure.

Regarding instrument approaches, the key information for matching the database to the chart is the procedure amendment reference date, not necessarily the date printed at the top of the chart. On charts published by the FAA, the procedure amendment reference date appears in the lower-left corner, next to the amendment number.

The best description of the procedure amendment reference date and how to use it is in Jeppesen Briefing Bulletin JEP 09-C (PDF)–even if you use charts published by FAA Aeronautical Information Services. The Jeppesen briefing bulletin includes a simple flow chart that helps you use the procedure reference date.

FAA published a safety alert (PDF) in 2009 that explains the difference between chart dates and procedure amendment dates.