Yesterday we went for a few practice instrument approach and on my first approach as I was getting closer to the airport, roughly 2 miles out, my needle (GRT system) start moving erratically from the far left to far right. We moved to a different and nearby airport for another approach, in a way to rule out localizer issue but got the same result. After a power cycle of the 430W, it was all OK. We tried three different airports, including the original practice destination and all with normal behavior. So, I was wondering if anyone has seen such behavior of the NAV or could this be the start of a problem to come. I guess since no other changes were made with the exception of a power cycle of the 430 in the air, I can rule out any cabling antenna issue.
Van's Air Force
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Erratic NAV reception
- Thread starter Bavafa
- Start date
This is the first thing I thought of but date doesn't seem right:
https://www.faasafety.gov/files/notices/2016/Jun/CHLK_16-08_GPS_Flight_Advisory.pdf
https://www.faasafety.gov/files/notices/2016/Jun/CHLK_16-08_GPS_Flight_Advisory.pdf
How does the 430 talk to the GRT? Via the ARINC link or the analog inputs?
I would hope it's something simple, like tarnished connectors. Pull the 430 and spray contact cleaner on all the pins. Same for the GRT connections. See if problem comes back. Intermittant electronics are the worst to track down.
I would hope it's something simple, like tarnished connectors. Pull the 430 and spray contact cleaner on all the pins. Same for the GRT connections. See if problem comes back. Intermittant electronics are the worst to track down.
The connection is via AIRNC and a GPS approach right before the power cycle worked as expected and like a charm.
I will be doing more approaches and testing to see if this comes back. I should have noted that the glide slop needle was steady and only lateral was erratic.
I will be doing more approaches and testing to see if this comes back. I should have noted that the glide slop needle was steady and only lateral was erratic.
Since the erratic behavior happened at two different airport, blocking the path to the localizer is less likely.Might have been something as simple as somebody taxiing in front of the localizer antenna.
I do have a splitter and I will check that should this repeat itself. Considering that this would have been nerve wrecking if I was on an IFR approach, I want to test it to make sure it is reliable. This is the first ever I had seen, hence my surprise.
I've thought some more. If it was a poor antenna or splitter connection the needle should have centered and flagged (on the GRT the needle would go hollow). So I'm at a loss to explain this.
Should this happen again, the 430 should be providing a 'awareness only' gps derived course on the moving map, which you could revert to in an emergency (or vfr).
Should this happen again, the 430 should be providing a 'awareness only' gps derived course on the moving map, which you could revert to in an emergency (or vfr).
PaigeHoffart
Well Known Member
What did it sound like?
This is a good reason to tune identify and monitor. We had issues with a FM radio station causing localizer interference, you could hear it while monitoring the ident. If it's a vehicle you can usually hear a flutter of static. It might also give you some warning of an intermittant antenna connection.
Paige
This is a good reason to tune identify and monitor. We had issues with a FM radio station causing localizer interference, you could hear it while monitoring the ident. If it's a vehicle you can usually hear a flutter of static. It might also give you some warning of an intermittant antenna connection.
Paige
