Garmin Updates GTN Trainer App

Garmin has updated the free GTN Trainer app for the iPad. The new version reflects system software 6.62, which includes features added since version 6.5, such as vertical navigation, along track offsets and more.

You can find a detailed discussion of some of these functions at New Garmin GTN 750 Features.

Use of GPS on Conventional Approaches (Update)

Users of Garmin GTN navigators may now use the GPS CDI for guidance along the final approach course of a VOR or NDB approach, provided they monitor the ground-based navaid to ensure that they’re tracking the proper final approach course. Previous editions of the AFM supplement for GTN avionics required you to display the VOR CDI on your HSI or PFD even if you could monitor the ground-based navaid on a separate CDI or by using a bearing pointer.

Note that you must still display the VOR/LOC (“green needles”) CDI to fly the final approach segment of an approach based on a localizer or any other type of navaid except a VOR or NDB.

For more information about setting the CDI while flying approaches, see
Setting the CDI on a Conventional Approach (The “Kill Switch”). For general background, see Use of Suitable Area Navigation (RNAV) Systems on Conventional Procedures and Routes

The updated language in the AFM supplement for the GTN series (see below) synchronizes the limitations in the AFM supplement with a 2016 update to AIM 1−2−3. Use of Suitable Area Navigation (RNAV) Systems on Conventional Procedures and Routes (see Use of IFR GPS on Conventional Approaches).

The change comes with a recent update to the system software for the GTN line of GPS navigators (more information about the new features at BruceAir here).

The new software brings a significant change to the language in the approved Airplane Flight Manual Supplement for the GTN boxes (the PDF of the new AFM supplement for the GTN 750 is available here).

Section 2.10 Instrument Approaches in that AFM supplement now notes the following:

…c) The navigation equipment required to join and fly an instrument approach procedure is indicated by the title of the procedure and notes on the IAP chart. Navigating the final approach segment (that segment from the final approach fix to the missed approach point) of an ILS, LOC, LOC-BC, LDA, SDF, MLS, VOR, TACAN approach, or any other type of approach not approved for GPS, is not authorized with GPS navigation guidance. GPS guidance can only be used for approach procedures with GPS or RNAV in the procedure title. When using the Garmin LOC/GS receivers to fly the final approach segment, LOC/GS navigation data must be selected and presented on the CDI of the pilot flying. When using the VOR or ADF receiver to fly the final approach segment of a VOR or NDB approach, GPS may be the selected navigation source so long as the VOR or NDB station is operational and the signal is monitored for final approach segment alignment. [Emphasis added]

A test of the new software in the free Garmin PC-based trainer indicates that the message warning the pilot to switch the CDI from GPS to VOR has also been removed. The following captures show the VOR-A approach at Paine Field (KPAE) north of Seattle flown with the CDI with GPS selected. Note the cyan bearing pointer behind the magenta GPS CDI.KPAE-VOR-A-XUKRE-G500TXi.jpg

KPAE-VOR-A-ARC-GTN750KPAE-VOR-A-ECEPO-G500TXiKPAE-VOR-A-ECEPO-GTN750KPAE-VOR-A-YAVUR-G500TXi KPAE-VOR-A-XUKRE-G500TXi

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.