[Mark Castle-Smith]

Sorry if this seems like a daft question. I have just finished a replacement panel in my RV7 and am about to start flight testing. I have installed a fairly standard AFS EFIS (3 screens - Greedy!!) connected to a GNS 530 and TruTrack DigiFlight II VSGV.

Part of the formal test I have to carry out as part of the LAA (UK Authority for Home Builds) official testing plan is to intercept a VOR with the autopilot, and record the maximum intercept angle achieved.

As a purely VFR pilot (but I do understand the theory of VORs) and never having had the pleasure of flying with such an integrated set up, I understand each of the manuals for the EFIS, Garmin and Autopilot, but am a bit lost when it comes to understanding how to set these up in conjunction with each other in order to to intercept and then track a VOR. Also what is the max intercept angle that can be reasonably achieved.

Sorry if this is a daft question, but there is no manual to cover the use of all three system together and this level of integration is new to me. But I understand from others with this set up, that the effort in learning them will be worth it in the end!

Many thanks for any help.

Mark

 

[DGlaeser]

VOR vs GPS

That is a bit of a 'trick question' since you are using GPS - which measures offset linearly, not angularly like a true VOR.
What they want you to do is set up a course that you are not currently flying, then fly toward it (in heading mode) and determine how close before the A/P captures. Find out if a linear offset value is acceptable.

 

[Mark Castle-Smith]

VOR

Thanks for the reply,

They do want a VOR track, and the GNS 530 does, as I understand it enable tracking to a VOR (after all it is a GPS,NAV,Com). So how do I do it with the 530, AFS EFIS and TruTrack!

Mark

 

[breister]

You don't.

The TruTrak DigiFlight II VSGV will only track an NMEA signal, and the Garmin 430 only outputs the GPS signal to NMEA.

 

[DGlaeser]

You don't have a VOR receiver...

Thanks for the reply,
They do want a VOR track, and the GNS 530 does, as I understand it enable tracking to a VOR (after all it is a GPS,NAV,Com). So how do I do it with the 530, AFS EFIS and TruTrack!
Mark

The NAV is GPS and ILS in the 530, there is no VOR.
The closest you can get is to select a VOR as a waypoint. Then you can put the GPS in Hold mode, which suspends auto-sequencing of waypoints and allows you to select the course to/from the waypoint. The CDI deviation from the selected course is linear, not angular, as mentioned earlier. Hopefully that will satisfy the requirement.
I don't believe the TT will track the ILS, but it will track WAAS GPS approaches.
I can't help with the specifics on how to use the AFS EFIS (I have a GRT Sport).

 

[zkvii]

Thoughts

Hi Mark,

Yes your right - you have the capabilities.... The GNS530 has Com, GPS and Nav functions. The switch between VOR and GPS CDI heading is shown in the bottom left of the display - VLOC or GPS is shown. VLOC is VOR localiser. Your VSVG will take vertical and horizontal steering commands so should be able to get a good intercept.

Did you wire the AP to be able to take direct 530 data feeds as well as AFS processed streams?

This is my best guess / I'm still learning the use of the instrument bit too. I would expect you should be able to dial up a CRS on the 530 with a tuned VOR, that will be your inbound radial. With VLOC selected the AP should then fly a 30, 45 or 60 degree (not sure which but I think probably 45) and then track on in. I haven't played with mine yet - on the list.....

HTH,

Carl

 

[fishguy]

Direct your question to Rob at AFS, he will give you your best answer. It should be possible with the EFIS interpreting the VOR signal from the 530 and directing the auto pilot.
FG

 

[Rainier Lamers]

I am not sure on how to do it with the AFS units but I suspect it is similar.

On our units you would select the horizontal deviation source to be routed to the HSI display - anything that goes to the HSI also goes to the autopilot if it can be steered via ARINC. We are also likely to do this with a normal NMEA system soon by "faking it".

So, it's quite simple realy - you have a lot of possible sources and you simply select which one to use.

Currently we do:
GPSNAV (that would be a "goto" or route following).
Simulated VOR (fly VOR radials even if you don't have a VOR receiver - using GPS to fake it).
Simulated ILS (We call it GLS, effectively a GPS based simulation of ILS).
Then real VOR/ILS from a number of possible sources connected to either serial ports (like a SL30) or whatever you can throw at the ARINC receive ports (there are three of them so you could select from three sources on the ARINC as well).
Of course you can also select a simple heading bug as source so you can fly a simple magnetic track.
The idea really is to connect up anything you want, tell the system what you have connected and then get presented with a selection of sources in flight so you can use whatever you want at the time.
It all boils down to a very simple thing at the end of the day - regardless of source you need to tell the autopilot to fly left or right and by how much (in effect by how much to bank).

Again, I don't know the AFS at all - but there will be something in there where you can select what you want the autopilot to follow. The EFIS should kind of be a "switch" for what gets routed to the autopilot.

Concentrating on your VOR question, assuming you selected the VOR as source and you selected the required radial using the OBS knob the VOR will now send "left/right" information to the EFIS. The EFIS will also have your magnetic heading and together with the VOR CDI and the OBS has all it needs to "plot" an intercept at a suitable angle onto the radial and fly towards it right until the point where the CDI starts centering - at that point (or shortly before) the EFIS will now direct your aircraft to track the radial (so depending on your OBS bearing you will be flying towards or away from the VOR station on the chosen radial).

Quite fun - just like with the real thing, things get "wobbly" just as you overfly the VOR station.

OK, here is something you can do for free (I.e.: Even works in a recession !):

Download our Odyssey simulator. Get some free navigation data from www.Navaid.com (which includes VOR stations) and convert that to something the simulator can use - (you create a navidata file using the free Enigma Flight Planner). Now you can configure the simulator to use "GVOR" which is the simulated GPS VOR.
You will find a GPS simulator - set it up for a suitable position and start flying in a particular direction and speed.
You will also find a autopilot simulator - switch it on. Now select a VOR station from your database and select the GVOR as source for your HSI. The HSI comes alive and you will see your simulated aircraft banking towards the selected radial - select this using the simulated knobs on the right (first select OBS as function for one of the two knobs).
If you go through the trouble of installing the terrain data and the vector maps (all of this is free for download) it gets quite neat.

The above is the short form - there is a lot to learn to get everything setup (just like in the real world), if there is interest I'll write up a step by step...

I know this perhaps is not what will happen with the AFS, but if anybody else out there wants to play with a big EFIS without spending a cent - this is one way to go...

Rainier
CEO MGL Avionics

 

[Mark Castle-Smith]

AFS/VOR/EFIS etc

Rainier (and all that have replied)

Thank-you so much for taking the time to reply so comprehensively., Exactly what I was after and very clear. I just need to clarify with AFS what is routed to the Autopilot.

Many thanks again.

Mark

 

[breister]

The NAV is GPS and ILS in the 530, there is no VOR.
The closest you can get is to select a VOR as a waypoint. Then you can put the GPS in Hold mode, which suspends auto-sequencing of waypoints and allows you to select the course to/from the waypoint. The CDI deviation from the selected course is linear, not angular, as mentioned earlier. Hopefully that will satisfy the requirement.
I don't believe the TT will track the ILS, but it will track WAAS GPS approaches.
I can't help with the specifics on how to use the AFS EFIS (I have a GRT Sport).

I think I was unclear in my prior post, but I saw an error in this that I thought worth addressing. The 430/530 series most certainly DO have VOR receivers installed; but the original question had to do with convincing the TruTrack unit to actually fly the VOR information which cannot happen with just the Garmin and TruTrak connected directly together.

If the goal is to have the TruTrak actually track the VOR signal (which the 430/530 DOES receive), you will be out of luck UNLESS your EFIS is capable of converting the VOR signal into NMEA / ARINC steering commands and you have wired the TruTrack to fly commands from the EFIS, not the Garmin. The Garmin will not convert the VOR signal to a format the TruTrak understands. For that, you would need to buy the Sorcerer model, or another that supports analog signals.

If the goal is to effectively fly the VOR radial but it is allowable to do so in GPS mode, I believe the Garmin allows an option to fly a GPS course from a GPS fix, thus simulating "flying the radial."

I know this sounds like splitting hairs, but although that will probably keep you within legal parameters of flying the VOR it is not actually the same thing. I know there was previously discussion about whether this would qualify as "flying the radial" but don't recall what the final legal resolution was. Others can explain that better than I.

Some EFIS units will take the analog VOR signal from the OBS output of the Garmin and convert it to ARINC. The down side of this is that you now have an additional point of potential failure between your receiver and your autopilot.

 

[orchidman]

If you have not already done it, I would suggest you go to the AFS web site and download the current users manual. Go to page 15 (EFIS Navigation) and you will be able to see the exact process for what you want to do.
The short answer to your question is YES you can.