Latest Info on VOR Shutdowns

The FAA recently provided an update on its plans to decommission about 30 percent (308) of the existing network of 957 VORs by 2025. The presentation, made at the April 2016 meeting of the Aeronautical Charting Forum, is available here (PDF).

Some highlights:

As I’ve noted in previous posts on this topic (e.g., here), the basic plan remains as follows:

  • Decommission about 308 VORs in two phases. Phase 1 runs from FY2016-FY2020. Phase 2 runs from FY2021-FY2025.
  • About 649 VORs will remain in service. In fact, many of those VORs will be upgraded to expand their service volumes.
  • Most of the VORs to be shut down will be in the Central (162) and Eastern (131) U.S. Only about 15 VORs will be decommissioned in the West.

The list of the first VORs to be shut down is available from AOPA here (PDF). AOPA also has good background about the program to decommission VORs on its website.

To provide backups should GPS signals fail or be disrupted, the FAA will retain a minimum operational network (MON) of VORs and MON airports that have ILS and/or VOR approaches.

Those MON airports and VORs are designed to enable pilots to:

  • Revert from PBN [i.e., GPS-based] to conventional navigation in the event of a Global Positioning System (GPS) outage;
  • Tune and identify a VOR at a minimum altitude of 5,000 feet above ground level or higher;
  • Navigate to a MON airport within 100 nautical miles to fly an Instrument Landing System (ILS) or VOR instrument approach without Distance Measuring Equipment (DME), Automatic Direction Finder (ADF), surveillance, or GPS where the capability currently exists; and
  • Navigate along VOR Airways especially in mountainous terrain where surveillance services are not available and Minimum En Route Altitudes (MEAs) offer lower altitude selection for options in icing conditions.

You can learn more about MON airports in this presentation (PDF) from the ACF meeting.

Use of IFR GPS on Conventional Approaches

FAA has published an update to the AIM, effective 26 May 2016, and it includes a big change if you have an IFR-approved GPS [i.e., a “suitable navigation system” as defined in AC 20-138 and AIM 1-2-3 (b).]

Now, if you fly a conventional approach based on a VOR or NDB (but not a localizer), you can fly the procedure entirely with the GPS, provided you can monitor (using a separate CDI or a bearing pointer) the VOR or NDB facility specified for the approach.

The new language is in section 1−2−3. Use of Suitable Area Navigation (RNAV) Systems on Conventional Procedures and Routes.

The summary of changes to this AIM update notes that:

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.

The new text in the AIM is in paragraph 5 of AIM 1-2-3:

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.

This change is the result of a discussion at the Aeronautical Charting Forum in 2014.

Changes in AIM Effective 26 May 2016

FAA has published an update to the AIM, effective 26 May 2016, and it includes several important changes of interest to typical general-aviation pilots:

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. [For more information about this item, see the detailed discussion here.]

3−2−3. Class B Airspace
This change adds an RNAV Receiver as an option for instrument flight rule (IFR) navigation requirement IAW 91.131 (c)(1).

3−2−6. Class E Airspace

This change updates the definition, vertical limits, and types of Class E airspace. The change more accurately reflects Class E airspace regulatory information in 14 CFR Part 71 and more clearly states that Class E arrival extensions have the same effective times as the airport surface area airspace….

4−3−22. Option Approach
This changes adds verbiage advising pilots to inform air traffic control (ATC) as soon as possible of any delay clearing the runway during their stop−and−go or full stop landing.

5−2−8. Instrument Departure Procedures (DP) − Obstacle Departure Procedures (ODP) and Standard Instrument Departures (SID)
This change adds language advising pilots what to expect when vectored or cleared to deviate off of an SID.

5−4−1. Standard Terminal Arrival (STAR) Procedures
This change adds language advising pilots what to expect when vectored or cleared to deviate off of a STAR. Pilots should consider the STAR cancelled. If the clearance included crossing restrictions, controllers will issue an altitude to maintain. It also adds language advising pilots when to be prepared to resume the procedure. Since all clearances on STARS will not include Descend Via clearances, the word “will” was replaced with “may.”

5−4−7. Instrument Approach Procedures
This change adds a note to provide guidance to pilots regarding what to expect when clearances are issued by ATC to altitudes below those published on IAPs.

Garmin GTN Avionics and RF Legs

The release of updated operating software for Garmin GTN-series avionics brings new capabilities to many typical general aviation pilots who fly under IFR. One of the new features is the ability to fly curved radius-to-fix (RF) legs on some instrument approaches.

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Until recently, RF legs were published only on so-called RNP procedures with authorization required (AR) restrictions (for more information, see AIM 5−4−18: RNP AR Instrument Approach Procedures). But FAA has started publishing some approaches with RF legs (like the example above) that are not designated as RNP AR procedures. And, with some limitations, pilots who fly aircraft equipped with GTN-series avionics should be able to fly the RF legs used as transitions/feeder routes on those approaches. (Note that so far, these approaches don’t require RF capability–conventional transitions/feeder routes and/or radar vectors are also available.)

For more information about RF legs, see RNP Procedures and Typical Part 91 Pilots and Garmin Radius to Fix Leg Project Report here at BruceAir. For additional background on GPS navigation and RNP procedures, see also Updated AC 90-105A.

The revised STC for the GTN series (document 190-01007-A5) notes that:

GPS/SBAS TSO-C146c Class 3 Operation
…The Garmin GNSS navigation system complies with the equipment requirements of AC 90-105 and meets the equipment performance and functional requirements to conduct RNP terminal departure and arrival procedures and RNP approach procedures including procedures with RF legs subject to the limitations herein [emphasis added].

Sections 2.12 RF Legs and 2.13.1 RNP 1.0 RF Leg Types of the STC add the following information:

2.12 RF Legs
This STC does not grant operational approval for RF leg navigation for those operators requiring operational approval. Additional FAA approval may be required for those aircraft intending to use the GTN as a means to provide RNP 1 navigation in accordance with FAA Advisory Circular AC 90-105. [Note that per AC 90-105A, domestic Part 91 operations do not require additional approval–only Part 91 subpart K operations and commercial operations need LOAs or the equivalent FAA approval.]

The following limitations apply to procedures with RF legs:

  • Aircraft is limited to 180 KIAS while on the RF leg
  • RF legs are limited to RNP 1 procedures. RNP AR and RNP <1 are not approved
  • Primary navigation guidance on RF legs must be shown on an EHSI indicator with auto-slew capability turned ON
  • GTN Moving Map, EHSI Map, or Distance to Next Waypoint information must be displayed to the pilot during the RF leg when flying without the aid of the autopilot or flight director.
  • The active waypoint must be displayed in the pilot’s primary field of view…

2.13.1 RNP 1.0 RF Leg Types
AC 90-105 states that procedures with RF legs must be flown using either a flight director or coupled to the autopilot.

This STC has demonstrated acceptable crew workload and Flight Technical Error for hand flown procedures with RF legs when the GTN installation complies with limitation set forth in Section 2.12 of this document. It is recommended to couple the autopilot for RF procedures, if available, but it is not required to do so. See section 4.5 of this manual to determine if this capability is supported in this installation.

At present, only a few non-AR approaches with RF legs meet the criteria in the STC and AC 90-105A. But RF legs could become more common on “standard” procedures to provide paths that offer better noise abatement, reduce airspace conflicts, and improve ATC efficiency, and pilots flying with GTN avionics (or similar navigators offered by other manufacturers) will be able to fly those procedures.

Updated AC 90-105A

FAA has published 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 (PDF available at the link).

AC90-105A

 

This update to the previous edition (published in 2009) contains many important changes for pilots who use GPS to navigate under IFR.

FAA is gradually adopting the concept of performance based navigation (PBN), which includes the old systems of area navigation (RNAV) and refines details of required navigation performance (RNP). For more details about these standards, see AIM Section 2. Performance−Based Navigation (PBN) and Area Navigation (RNAV).

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.”

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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.

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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.

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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.

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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.

Changes to Flight Plans with Procedures in GTN System Software 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 most important changes, at least for day-to-day operations for typical general aviation pilots, is how loading (or activating procedures) affects departure and destination airports in flight plans (routes).

To learn about and practice using the new features, 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.

I have experimented with how the new system software in the free GTN 750 PC Trainer Lite available from Garmin, and the following examples illustrate the changes and offer suggestions to help you adapt your personal techniques for using a GTN-series navigator in the cockpit. In particular, I offer suggestions for displaying information about your destination airport (frequencies, current weather, and so forth).

To learn about the new ad-hoc hold feature in the updated software, see Flying Ad-Hoc Holds with a GTN 750 here at my blog.

Basics of the Change

First, here’s a note in the updated Pilot’s Guide for the GTN 750 that describes how software version 6.x changes flight plans (routes) when you load an approach (or, it turns out, a departure procedure).

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Now let’s look at how this change affects when and how you load and fly a typical instrument approach.

A Typical IFR Flight Plan

Suppose you plan to fly from Boeing Field (KBFI) in Seattle, WA to Spokane International Airport (KGEG) in eastern Washington. Here’s a route across the Cascades that I often fly in my normally aspirated Beechcraft A36.

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Note that the first and last waypoints in the flight plan are the departure airport (KBFI) and destination (KGEG). ATC typically assigns a SID when departing Boeing Field. When runway 13R is in use for IFR departures, your clearance includes the KENT7 (or the current version) SID, which you load as follows.

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Note that after you load the departure, KBFI no longer appears as a waypoint in your current flight plan. The first waypoint in the flight plan is now the runway ((RW13R), which is the first fix in the KENT7 SID. The IDs of the departure and destination airports, however, remain in the title of the Active Flight Plan.

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Here’s the first tip. If you use your GTN navigator to retrieve frequencies and other information about your departure airport, collect that data before you load a departure procedure.

Now assume that you have departed KBFI, followed the SID and ATC vectors to join V2, and proceeded to a point west of Spokane where you are preparing for the arrival and approach at KGEG, say the RNAV (GPS) RWY 21 Y approach.

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Given that you’re approaching KGEG from the west, ZOOMR is good fix to choose, at least initially, as the transition for the approach. ATC will probably provide vectors, but with all the fixes from the west now in the flight plan, it’s easy to accept a clearance direct to any of the fixes or legs along the path to the final approach segment.

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Notice that after you load the approach, the GTN removes KGEG from your active flight plan—unless the active leg of your flight plan includes the airport. Versions of the system software prior to 6.x always added the approach name and fixes for an approach below the destination airport.

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A Logical Change?

The change in behavior in version 6.x may disrupt your habits at first. But it also may reduce the potential for errors when you load and fly an approach (or DP) under typical circumstances.

The new behavior provides a seamless transition from waypoints in en route section of your flight plan to fixes in an approach. You no longer have to scroll below the destination airport in the active flight plan list to select an initial fix or to activate a leg of the approach you’ve loaded into the GTN.

A Change in Tactics?

The new behavior described above may lead you to change your basic technique for loading an approach.

I have long advocated loading procedures as early as possible—even before taking off if the destination is nearby—to reduce your workload during busy phases of flight. The new behavior in GTN software version 6.x, however, suggests a change in tactics, at least under some circumstances.

If you can determine well in advance which approach you prefer to fly—in-cockpit weather can give you an early alert about which runway is likely to be in use long before you can receive the ATIS or AWOS (that is, the one-minute weather at a non-towered airport)—then loading the approach you prefer or reasonably expect to fly is still a good idea. Just take a moment before you load the procedure to retrieve and note frequencies and other details about your destination airport from the GTN.

Pilots arriving or departing an uncontrolled airport that has automated weather broadcast capability (ASOS/AWSS/AWOS) should monitor the broadcast frequency, advise the controller that they have the “one−minute weather” and state intentions prior to operating within the Class B, Class C, Class D, or Class E surface areas. (AIM 4-4-6)

ONE-MINUTE WEATHER− The most recent one minute updated weather broadcast received by a pilot from an uncontrolled airport ASOS/AWSS/AWOS. (P/C Glossary)

If you prefer to wait until you are closer to the airport, or if ATC clears you direct to the airport or issues vectors before initiating an approach clearance, you can delay loading the approach.

If you wait until the active leg of your flight plan includes the destination airport, the GTN adds the approach below the destination airport, just as it did prior to version 6.x.

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Or, as shown below, you can load a procedure early and then add the destination airport to the bottom of your current flight plan, so that the airport is still available as a reference and to provide easy access to the information about the airport in the GTN’s database. Here I’ve added KGEG below GANGS, the MAHP for the RNAV (GPS) RWY 21 Y approach. It’s easy, as before version 6.x, to touch the airport ID and then select Waypoint Info.

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Add an Alternate?

The change in version 6.x also simplifies adding an alternate to your flight plan.

Suppose the weather at KGEG is close to minimums as you begin your arrival. Adding an alternate airport to your flight plan before you miss the approach could reduce your workload during a critical phase of flight.

Here I’ve added Walla Walla, (KALW) as my alternate after the MAHP at GANGS.

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Now I can quickly retrieve information about KALW and even load an approach as soon as I get a new clearance from ATC.

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This technique would also be handy during training flights, when you fly several approaches, either to the same airport or close-by fields.

Other Methods for Retrieving Airport Information

If you prefer not to fuss with the way version 6.x handles airports in flight plans that include procedures, you can still retrieve information about airports from the GTN’s database, even if your departure and destination airports are no longer in your active flight plan.

For example, touch the map, scroll to display an airport, and touch an airport symbol. Touch Waypoint Info to display details (frequencies, current weather, runways, NOTAMs, and so forth) about the airport.

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You can also use the Nearest Airport feature (available from the Home screen) to gain quick access to details about your destination—provided you’re not too far away.

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Or you can use the various search option in the GTN to find an airport and retrieve information about it.

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More to Come

I’ll have more to say about the updated system software after I’ve had it installed in my airplane and explored the new features on test flights. Stay tuned.