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Need some 430W / Dynon help

airguy

Unrepentant fanboy
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I'm just finishing up my instrument training, getting ready to take my practical, and I'm trying to diagnose a problem with coupled approaches.

My equipment is full Dynon Skyview Classic, with the ARINC-429 being fed from a Garmin 430W. It works absolutely great for coupled approaches on the RNAV (GPS) side, and when I move the Skyview HSI source to the 430W NAV side I can see the ILS glideslope just fine, BUT the ILS course is always set to 150 degrees and the autopilot will try to turn to 150 degrees regardless of what the actual ILS course is. I have to use the localizer display on the 430W itself and the glideslope display on the Skyview HSI to hand-fly the ILS.

What am I missing here? How do I get the 430W to adjust the Skyview HSI (and autopilot commands) to the correct heading on the localizer? It will lock on and follow the localizer just fine in GPS mode - but NAV mode always brings it to 150 degrees. I'm suspicious this is a configuration problem since 150 degrees is the default test heading put out by the 430W on power-up self-test, but I've been unable to find a configuration problem so far. As a troubleshooting point, I know that the "bearing source" displayed on Skyview HSI will correctly show direction to VOR's being received on the 430W, so I know the connection between the NAV side of the 430W and the ARINC appears good. So far I've been doing this with the autopilot in heading control and NAV armed to capture, and when it captures it just obediently follows the HSI and turns to 150 degrees regardless of the actual localizer direction.

Any ideas?
 
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Don't know much about the Dynon, but the 430 doesn't provide a magnetic course for the localizer. It is a simple CDI. 430 provides number of degrees off course, based upon an interpretation of the radio navigation signal received.

On my GRT, it does provide the actual localize course, in degrees, but it gets that from it's own navigation database and also asks the pilot to confirm it is correct before setting the HSI to it. My guess is that Dynon doesn't do such an operation and it requires the pilot to dial in the course if you want the proper course indication to appear on your HSI. I would assume the OBS knob would perform that function. This is routine for 6 pack pilots. They manually dial in the course on the HSI and maybe Dynon wanted to emulate that.

Remember, with ILS there is no broadcasted course, only broadcasted/interpreted deviation from the course line layed out in the IAP and orchestrated with directional positioning of the antenna.

The Dynon AP should be following the CDI for directional guidance, not the course set in the HSI on an ILS. I would venture that you need to tell the Skyview that your are doing a LOC/ILS approach and not a GPS approach. There should be an AP source function and you need to be selecting VOR/LOC/ILS and not GPS or TRACK. This is pretty basic for EFIS, so there must be a setting somewhere. TYpically you approach the LOC via GPS guidance and then inercept LOC course. This requires a change in the EFIS/AP to move from a Track based guidance to a CDI based guidance. I know some do this automatically, bus suspect some require manual intervention. Some see the change when you switch to VLOC mode on the 430.

Be advised, for your test you need to know that the ILS approach is only legal if your AP is following the CDI. You are not legal if your AP is following a magnetic course reference while on the ILS course, no matter where it came from. I suspect that some examiners would fail you for this if they noticed that was happening. Hand flying, you can follow whatever you want, but still must maintain a specific CDI deviation tolerance.

Also, if you don't switch the 430 from VNAV mode, I believe it does provide GPS guidance down the course. It is critical that you switch it to VLOC mode once on the course to be legal. This change can occur automatically in the 430, but requires the correct settings in the 430. I am pretty sure the examiners look for that, as it must be a common mistake.

Larry
 
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Another method is; once established on the localizer, go the G430 flight plan screen and select "direct" to the runway. Then everything works as expected. There is more than one way to skin this cat.

;)


Be careful with doing it this way. It might work most of the time, but DIRECT TO is to the center of the airport, while the localizer is lined up with the runway centerline. The best and correct way is to use the course knob on the EFIS or the knobs panel and enter the inbound course as depicted on the approach chart.

On the new AFS software, a window pops up reminding you to set the inbound course. It's pretty cool.

Vic
 
Greg I think you have a configuration problem. I have the identical setup and have it set up so that ILS approaches are automatic. I have the GPS set to automatically switch to ILS mode when in proximity to the Loc and the Dynon is also set to switch the HSI to the correct input.

When flying you configure the radio for the approach and just fly the needle to the initial or vectors until established. When you are near the course the radio automatically switches you go from a magenta to a green arrow and you get the glideslope indicator. If hand flying just follow the arrows. If on autopilot it will fly the localizer but you must push the VNAV button to follow the glideslope.

PM me your phone number and I can text you my radio settings.
 
What Ted said is correct - if you configure the SkyView to automatically shift from GPS to LOC/ILS. I prefer to keep this a manual shift. Just decide what you want.

Carl
 
OK, the various parts are starting to come together and make a little sense to me now. I haven't had a chance to try it yet, but here's the way I have it right now.

First, I have autoswitching disabled - doing it manually on both the 430W and the HSI source on Skyview. I have noticed that if I dial in the ILS approach, the localizer shows correctly if the Skyview is looking at the GPS side of the 430W, but the NAV side of the 430W as a source gives 150 degrees regardless. If I leave it on the GPS side, the autopilot will capture and fly the localizer just fine but it will not display a glideslope for me since that comes from the NAV side.

If autoswitch is enabled, and the approach starts from the GPS side, then HSI course should automatically be set from the GPS side of the 430W. Then when you pass the IF and that FAF leg comes active and the 430W switches to VLOC mode, the Skyview should follow that switch and go to the NAV side of the 430W for CDI deviation correction while still following the preset (from the GPS) course of runway heading.

Correct?

I'm curious about this because, today when manually switching the PFD HSI source from GPS to NAV side, it does NOT carryover the course direction. It must be something in the automatic switching that carries that over?
 
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Be careful with doing it this way. It might work most of the time, but DIRECT TO is to the center of the airport, while the localizer is lined up with the runway centerline. The best and correct way is to use the course knob on the EFIS or the knobs panel and enter the inbound course as depicted on the approach chart.

On the new AFS software, a window pops up reminding you to set the inbound course. It's pretty cool.

Vic

Didn't think about that small issue but you are correct. :cool:
 
I'm curious about this because, today when manually switching the PFD HSI source from GPS to NAV side, it does NOT carryover the course direction. It must be something in the automatic switching that carries that over?

As I mentioned above, 430 does not provide a magnetic course in VLOC mode. I believe the TSO specifies that guidance on the ILS or LOC approach must be CDI and therefore th3 430 stops sending it in VLOC mode. The course on your HSI can be a situational awareness aide, but cannot be used as official LOC guidance, therefore the 430 doesn't provide it. The LOC course must therefore be manually entered or determined by the EFIS if it has access to IAP's or runway headings.

Larry
 
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Carefully reading through the documentation, it appears that only the CDI deviation data switches from the GPS to the NAV side on the 430W, and the 430W utilizes something they call an "OBS resolver" that apparently, from what I can ferret out of the docs, acts as a "target" for lack of a better term for the autopilot to go toward and then take CDI deviation from that target. In theory, given enough time, it would finally correct itself just like a GPS course with a massive crosswind would, but on initial startup (like when manually switching to NAV source) it will turn toward the target course immediately and then start making corrections. Using the CRS knob on the Skyview to set the course to the proper runway alignment should communicate that OBS back to the 430W through the ARINC-429 and feed that into the OBS resolver, which then will send appropriate-magnitude corrections to the autopilot, if it works the way I think it does.

The Bendix-King KLN94/KMD550/KAP140 GPS/autopilot installed in late-model C-172's will do the same thing now that I think about it, you needed to dial in the "DTK" readout from the KLN94 display into the HSI for it to capture quickly - otherwise it would hunt drunkenly around the compass for several minutes before settling down into somewhat the correct direction.

It's starting to make a little sense now, but it will be tomorrow afternoon before I get a chance to test it.

In all fairness I'll point out that this agrees completely with all the advice given by Larry, Ted, and Carl - I'm just trying to figure out the "why" behind the "what".
 
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Carefully reading through the documentation, it appears that only the CDI deviation data switches from the GPS to the NAV side on the 430W, and the 430W utilizes something they call an "OBS resolver" that apparently, from what I can ferret out of the docs, acts as a "target" for lack of a better term for the autopilot to go toward and then take CDI deviation from that target.

OBS only works on VOR navigation. OBS doesn't apply to LOC signals, as they are designed only to allow navigation down the preset course, unlike the Onmibearing VOR, that allows the pilot to select the course to or from the VOR (it effectively broadcast all 360 segments). The 430, or any Nav receiver, will ignore the OBS selector data when tuned to a LOC freq.

The 430 will not provide any bearing or course data for LOC guidance, beyond the deviation data that is receiving over the air, when in VLOC. No DTK or similar. It only provides course deviation, derived from the broadcast signal. Only your HSI or EFIS can establish a desired magnetic course indication for you, with no help from the 430.

The why is the TSO. The FAA makes it very clear that LOC/ILS approaches are to be flown based upon deviation data from the broadcast signal and not from magnetic course.

Unfortunately I can't answer WHY the Dynon wants course data to fly a LOC approach. It should be flying off CDI data. Though I fully understand how the course data will help with intercept. I think most AP's want you inside of full scale deflection and asssumes you are pointed at the airport, so don't need course data. These are usually limits that must be met before an armed mode will switch to active.

Also, remember that the 430 isn't driving the AP. It is only providing basic data that an AP can use to fly. Nav data is far more limited than GPS data. It provides no direction to help the AP intercept. This excludes GPSS data which is specifically designed as instructions for the AP.

The 430 does help with intercept by flying in VNAV GPS mode up until intercept before switching to VLOC, so that it can be more involved in intercept for the AP.

Larry
 
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Circling back on this thread - all is well. I figured out the buttonology and it works as advertised, shot three coupled ILS approaches today intercepting at various point and it was all happy-happy.
 
Circling back on this thread - all is well. I figured out the buttonology and it works as advertised, shot three coupled ILS approaches today intercepting at various point and it was all happy-happy.
OK, so what "buttonology" did you wind up using? Inquiring minds want to know. :D
 
OK, so what "buttonology" did you wind up using? Inquiring minds want to know. :D

Well the core of it, once I identified and fixed a broken wire feeding from the NAV side of the 430W to the 429, was enabling the autoswitching on the Dynon and then STOP TRYING TO do the job of switching from GPS to VLOC. I was not understanding just how easy it was to allow the 430W to switch the Dynon, and how well the Dynon accepted that. My IFR instructor cautioned me several times about making sure the 430W was in VLOC mode on an ILS approach, calling it the "$500 button" (for the cost incurred if I failed to switch during the checkride), and that had me in the mindset that I had to make a forced switchover.

With the wiring corrected, and in autoswitch mode, all you have to do is select the approach on the 430W, and set the autopilot for heading/altitude to intercept somewhere on the approach with NAV armed and it will capture like a charm. Once established inbound and the glideslope comes alive, arm the VNAV and enjoy the ride. I was trying to make it harder than it needed to be.
 
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