G1000 troubleshooting - finicky ILS and LOC issues

[briankelly327]

Posting to the forum before engaging the $135/hr avionics shop...

On some recent flights, Ive noticed that when dialed into an ILS or Localizer approach, the box to the left under the HSI does not display distance-to. I have a 2006 DA-40 without WAAS or DME, but I seem to remember a point when this window would have the localizer name and distance, using GPS to fill in the distance-to. Strangely, this box still works with VORs when dialed into NAV 1 and NAV 2, the boxes next to the CDI show both name and distance to the VOR.

Then: On my most recent flight into KFXE, it was night and visual conditions, but being the first time flying there I asked for ILS 09. I selected the approach on the G1000, the correct frequency loaded in NAV 1 and 2, I swapped CDI to show the green localizer which was set to the correct heading, and Miami approach gave me vectors to final. The NAV 1 however never identified the ILS. I pushed the NAV volume and turned it up but couldn't hear any ID code either. As I got closer, the localizer came alive and was working correctly. It was visual and I was perfectly aligned with the runway but uncomfortable knowing that I didn't successfully ID. I flew the ILS in visual conditions, the localizer and glide slope were spot on, but I was unable to identify and the distance-to box next to the CDI was blank. On my subsequent flight, I was able to ID VORs and get distance-to no problem. So it seems to be an ILS and localizer only problem.

I asked tower if there were any known or reported issues identifying the ILS and they said I was the only pilot to mention it.

Anyone here know the inner workings of the G1000 and its LRUs to help trouble shoot? Or anyone experience similar ID and distance-to issues with their systems? Its just strange that these functions work with VORs but not for ILS / localizer.

Thanks!
Brian

[pietromarx]

Some questions:

Did the ILS/LOC ID correctly in NAV 2?

Have you done any software updates recently?

What was the flight plan you put in? (Was there a flight plan in the G1000 or were you flying it ad hoc?)

Did the system show you the distance in the flight plan?

[Rich]

The failure to show the LOC ident is puzzling, but I seem to recall that Garmin doesn't have the location of the localizer antennae in the databases. And the distance from the LOC antenna isn't particularly useful in any case.

I do know that the documented (and actual) behavior for the 530 is to show ident, bearing and distance for VOR's when the signal is received, but when it's a ILS/LOC, it displays ident, airport ID and approach type and runway (e.g. "ILS 16R").

FWIW I perused the manual I have for the G1000 and it doesn't seem to show a screenshot where LOC distance is depicted.

[linzhiming]

As far as I know, the ILS box does not show a distance indication - I have never seen one on my plane and the G1000 simulator for PCs exhibits the same behaviour.

For that reason, I check the CIxx and FIxx and the MAP waypoint distances to each other carefully during the approach briefing after the procedure has been loaded so that I can use the GPS waypoints as substitute for distance. Please note that the MAP waypoint for ILS approaches (should it be used for a LOC approach for whatever reason) normally refers to the start of the runway and therefore distance shown is in reference to the runway and NOT the LOC DME-equivalent distance!

Wolfgang

[linzhiming]

The NAV 1 however never identified the ILS. I pushed the NAV volume and turned it up but couldn't hear any ID code either. As I got closer, the localizer came alive and was working correctly. It was visual and I was perfectly aligned with the runway but uncomfortable knowing that I didn't successfully ID.

As the behaviour not to show distance is normal (see my other post), this should be a genuine reception issue or issue with their LOC ID signal and not an issue with your G1000. Did you press down the NAV VOL button to activate ID mode after pressing the NAV1 button on the audio console?

The G1000 does not ID localisers and other navaids using the database but genuinely listens to the morse code ID on the frequency. I have had a few rare instances where the LOC ID did not show - during the most recent one, when I listened to the ID, I could hear some static radio interference on the frequency, which is why the G1000 did not ID the localiser. The LOC CDI signal worked but I treated it with caution given the radio interference I heard. As I got closer to the runway, the ID came up as the interference ceased (presumably as the LOC signal got stronger as I got closer to the runway and therefore transmitter).

Wolfgang

[briankelly327]

Got it - so seems like its normal not to have the distance-to ILS/LOC in the box next to CDI. Ive been using the flight plan GPS fixes and distances as my primary and VOR radials as backup to identify fixes. On an ILS-DME approach with fixes identified using ILS distances, do you simply use the GPS to identify step downs?

Regarding the ID issue, I was on a flight plan loaded into G1000, and loaded the approach through the G1000, not ad hoc. Flight plan correctly showed distances. Both NAV 1 and NAV 2 failed to ID the ILS. And I pushed the NAV volume button and turned it up and couldn't hear any code to identify either. I need to go up for some practice approaches to other local ILS and see if it was a site specific issue or if its also happening on other ILS approaches.

And I did have the avionics shop do a software reset recently to correct a failed data path error, which was why I was concerned this was a G1000 issue.

Thanks for the input here.

[eireengineer]

Good day Aviators, I suspect, via an avionics tech., that the ILS/VOR antenna maybe bad. Diamond says it’s integral with the horizontal stabilizer and only way is to replace the horizontal stabilizer!$$$$$ In my experience the creative solution is to abandon the VOR antenna in the stabilizer and install a new antenna on the fuselage or other location per Diamond’s approval. Has anyone had to replace their ILS/VOR antenna in there DA40, 2008, G1000 or similar aircraft?

[Steve]

Daniel - I don't know what level of troubleshooting your avionics tech has done, but cable and connector issues are way more common than the antenna itself going bad. A cable/antenna analyzer should point you in the right direction.

[eireengineer]

Good night Steve, Thank you for your comment. I will pass your recommendation on to the avionics TEC in PR.

[Karl]

Good day Aviators, I suspect, via an avionics tech., that the ILS/VOR antenna maybe bad. Diamond says it’s integral with the horizontal stabilizer and only way is to replace the horizontal stabilizer!$$$$$ In my experience the creative solution is to abandon the VOR antenna in the stabilizer and install a new antenna on the fuselage or other location per Diamond’s approval. Has anyone had to replace their ILS/VOR antenna in there DA40, 2008, G1000 or similar aircraft?

It is unlikely to be the actual antenna, but there is an SB to fit external ILS/VOR antennas.