I flew an ILS today and was at the proper altitude to capture the ILS and the 540 showed VLOC in the upper right hand corner. No glide slope.

I get a glideslope when flying an LPV approach. There was no NOTAM re the ILS being out and I was getting vectors from ATC.

Help.

Have you ever seen a glideslope with your IFD installed, when flying an ILS?

Do you have a second NAV radio? If so, do you see a glideslope indicated there?

* Orest

Let’s say I am flying along without a flight plan in the IFD 540. I’m flying in the vicinity of an airport that has an ILS. Can I tune the ILS frequency then manually select LOC (instead of GPS) as my guidance source and manually fly the Glideslope?

Or is the unit designed such that an approach must be loaded as part of a flight plan in order for the unit to behave as a good old fashioned ILS/VOR receiver would in similar circumstances?

Interesting question. I have not flown an ILS without having it selected and loaded in the flight plan, so I can't give you a definitive answer, but I have certainly selected VORs on the IFD that are not in the flightplan, and viewed them in my EHSI.

I would be very surprised if you needed the approach loaded in the flight plan, for the VLOC receiver to work, but you may need to select VLOC manually.

* Orest

FWIW - I started this preflight check just over three years ago after noticing during a VFR flight that my GI-106A would not depict VHF signals (VOR & ILS) even though the IFD540 and GI-106A indicated VLOC and the IFD540 properly decoded the VHF stations. I could also aurally decode the VHF stations through the IFD540. Cycling between GPS and VLOC did not resolve the issue; additionally, all GPS indications on the GI-106A were normal. After landing, a restart of the IFD540 corrected the issue. 

My working theory was that there was a rare error in the boot up "handshake" between the GI-106A and the IFD540 that caused the issue and I just wasn't aware of it until I switched to VLOC for the first time near the end of that flight. I suspected that if VLOC indications were verified before flight, they would continue to work without issue until at least the next IFD540 restart. I certainly did not want to be surprised by this issue while IFR, hence the start of my preflight check.

I have since caught this very rare issue once or twice out of hundreds of preflight checks. The last time was over a year ago and I believe prior to IFD s/w 10.2.3.1. In both instances, the issue was corrected with an IFD restart. Additionally, I have never seen the VLOC indications on my GI-106A not work properly during flight after they had been verified to work properly prior to flight.         

Stevei wrote: RE IFD 540. A while ago I posted that I didn't get a glideslope when flying an ILS. It was suggested to check my settings, which I did...

Just to clarify, when you say "I didn't get a glideslope," you mean that the vertical deviation indicator is absent on your navigation display?  Meaning, no glidepath needle, or no movement of it, appears at all? 

The other possibility may be just that your autopilot is not capturing the glideslope, but if you're not seeing any glidepath indication it's not an autopilot problem.  I just wanted to clarify so as to rule that out.

If you see no glidepath indication, did you get the GPS->VLOC indication in the upper right corner of the IFD when loading the approach?  And did you see it change to VLOC when the 5 parameters in the pilot's guide were met?

The IFD has to feed this info to your navigation display.  I wonder if the signal from the IFD to your display uses different wires or connections for the LPV and ILS glideslopes.  If so, perhaps the pathway for the ILS glidepath signal is compromised.

I lift my glass to you, fellow pilot. That's an excellent preflight check and I'll add it to my own repetoire.

Yes, it works just fine that way (entering the localizer frequency and selecting VLOC on the IFD).  Absent other navigation sources (VOR, DME, NDB, etc.), you may not be able to locate certain initial or intermediate fixes on the approach, but if you know you're on the right course to intercept the localizer, then it works just as it would using a non-GPS navigation radio (such as a KX-155).  And you don't need to be on the final approach heading as the localizer coming alive indicates when to turn to the final approach course.  The glide slope indicator will become active at the appropriate point and you would follow it down to the DA just as you would if the approach were loaded in the IFD.

I don't recall the specifics, but there is a label that has to be properly set in maintenance mode in order for the glide slope to display.  I know this because I had the same issue.  Check with customer support.  If you aren't getting the answer, let me know and I'll find the email I received from Avidyne that provided direction for correcting the issue.

JF

I know that this is an old post but saw no final solution.   I had a similar issue with my Nav 2, a Garmin GNC255A.  I would get no glide slope at all on it but would on the IFD540.  Turns out that the unit was mis-wired, I can't exactly recall what it was but after that, all was good.

I  having this exact same experience and tested it once again yesterday.  I’ve never had a glideslope appear on my GRT EFIS nor has it been flown by my AP.   This was a G430 replace and GS worked as expected.  No wiring changes since then.

I will check that my parameters match Stevei’s.

AZ Flyer, if you have some additional information please post or forward.

Avidyne support, can you recommend next actions?  I don’t have a 2nd Nav setup to drive my EFIS.

Thank You.

Best bet is for you to either call or email Avidyne tech support.  1 888.723.7592 or pilotsupport@avidyne.com.