AV-HSI Feature Overview

AV-HSI Feature Overview (Video Transcript)

This video provides an in-depth overview the AV-HSI. The AV-HSI allows the AV-30 to be the primary navigation indicator for IFR flying. It interfaces with GPS and VHF navigators to provide enroute and approach guidance, including ILS approaches and GPS approaches down to LPV minimums.

Whether you're an experienced instrument pilot or an instrument student, uAvionix believes that you're going to like what we've done with this product. Additionally, in this video, we will walk through the AV-30 modes and interfaces while using the AV-HSI.

Let’s first begin with an overview of the AV-HSI itself. The AV-HSI is small and packs a lot of capability. In short, it converts the ARINC 429 interface found in IFR navigators into an interface usable by the AV-30. It interfaces with a GPS source and a VHF source, whether they're from the same unit, like a GNS430, or from a standalone GPS and a standalone NAVCOM.

The AV-HSI also interfaces with up to four AV-30, serving navigation data to all four and acting as an information hub that synchronizes data between the AV-30s. The installation manual and pilot guide for experimental aircraft are available under the support tab at uavionix.com/support. This video doesn't replace those manuals, so please take some time to read them.

The AV-30 can alternate between having a traffic display, attitude indicator (AI), directional gyro (DG), and course deviation indicator (CDI). With the AV-HSI, the AI, DG, and CDI will show both lateral and vertical guidance.

For the attitude indicator (AI) mode when running with the AV-HSI, the lateral and vertical deviation bars, like other overlays, can be enabled or disabled. Additionally, there is a nav mode and OBS overlays that can be added. The deviation indicators are magenta for GPS sources and green for VHF nav sources.

To declutter the screen, the vertical deviation bar will only show up when glide slope data is available from your navigator. For ILS approaches, this happens when your radio is tuned to an ILS frequency and is receiving a signal. For GPS approaches, this varies by the approach type. Check your GPS manual for details.

Note the lateral deviation indicator is an arrowhead shape. The arrow pointing up is a two indication. If we were navigating on a radial from a station, the arrowhead would point downward.

Moving onto the directional gyro (DG) HSI mode. Like the attitude indicator, the glide slope indicator shows up when glide slope data is available. Another useful addition is the bearing pointer for VOR stations. The bearing 2 station was always there for GPS, but there is now VOR.  Again, GPS is magenta, VHF is in green. The current nav mode overlay is also available and can be put in any of the six overlay spots.

Without the AV-HSI, the course deviation bar has a set scale of one nautical mile per dot, and the HSI mode is limited to VFR only. When flying with the AV-HSI, the scale varies by the navigation or approach mode, and this guidance can be used for IFR flying.

In this overview video, you will note a graphical to and from indicator. The arrow points towards the tail of the deviation bar when flying from a station and toward the head of the deviation bar when flying to a station. The same graphical to from indicator will be present when flying a radial off a GPS point. The VOR indicator has a scale of five degrees per dot.

The heading can be tied to DG or GPS track. When flying vectors from ATC, you'll want to use DG, but once on an approach, some have come to prefer GPS track because it takes away the guesswork of compensating for wind.

Moreover, the DG arc mode in the original AV-30 would only display the current navigation waypoint and is something often not found in instruments of this size or price point. The 2.4.1 software release expanded to display a full flight plan. The AV-HSI in version 2.6.0 takes us further by adding curved waypoint segments, including holding patterns and DME arcs. Just like the attitude indicator, lateral and vertical guidance overlays are available.

It's important to note that the moving map itself should be used for situational awareness only. It doesn't zoom in enough to be used as the sole navigation resource for approaches and is labeled as VFR only for that reason. The lateral and vertical deviation overlays, however, provide IFR approach guidance. Again, bearing pointers for both GPS and VOR are available on screen.

Next is the course deviation indicator (CDI). As with the other modes, it'll show lateral and vertical guidance for both GPS and VHF navigators. The outside compass ring is tied to the OBS setting.

For GPS and ILS approaches, the OBS doesn't matter. It comes into play when tracking a VOR or a radial from a GPS fix. As with all the other modes, there are several user-configurable spaces available for data overlays.

They can be turned off entirely to declutter if you prefer. We've made two CDI pages. Some users typically have one set up for the data they want for approaches, and one set up with the data they want in route. As with the AI, DG, and MFD, the last page brings up a reversionary attitude indicator. Bearing pointers to GPS and VORs are available. The navigation mode is enunciated in the background.

Now that we've discussed all the operating modes, we can move onto the user interface. Knowing the workload of single pilot IFR, we tried to keep things simple and consistent with our current AV-30 workflows. There are two additional controls in the push set menu: navigation source select and OBS.

AV-30 users will be familiar with pushing the center button to cycle through items in the push set menu. Setting the navigation source is no different.

First, press the center button until you see source select. Then, rotate the center knob to select either GPS or VLOC. If you're using an all-in-one GPS NAVCOM like this Avidyne IFD540, switching the source in the navigator will also switch source on the AV-30s.

The next menu option sets the omni bearing selector (OBS). There's an auto mode that will automatically set the OBS from the GPS flight plan or the center knob can be rotated to dial in a specific course. A long hold of the center button will automatically set the OBS to the current bearing to station.

This instructional video shows VOR guidance, but GPS works the same way. The AV-HSI networks up to four AV-30s together, so when you change a parameter on one, it gets changed on the others as well.

Currently the AV-HSI will synchronize heading bug, nav source, OBS, set altitude, set vertical speed, autopilot mode, baro, and any manual DG adjustments you make. Additionally, the AV-HSI shares data from an outside air temperature probe, so if one AV-30 has an OAT probe, all the AV-30s will get the data. This synchronization is a good time saver, though synchronization of each parameter can be turned off individually if you prefer the AV-30s to operate more independently.

Lastly, the AV-HSI continuously compares the attitude solution of each attached AV-30. If any of the connected AV-30s disagree on pitch or roll, an alert will pop up. Think of it as an aid to your normal instrument cross scan, only this cross scan happens automatically several times a second.

If you have any questions, please reach out to us by submitting a support ticket. Until next time, wishing you safe and happy flying wherever your journey takes you.