Intermittent GPS Outage on a Wonderful 430W

Pilot Steve

Pilot Steve

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Pilot Steve
I'd never had a GPS outage on my 430W until the planned GPS jamming testing this year. But now I'm having them more often in flight.

My avionics shop said they would replace the antenna first and check the connections but I'd love to hear from anyone else that has had a similar issue.

On my last flight, I lost the GPS data, regained it in 30 seconds or so, and then lost it again for another 30 seconds. After that, it was fine for the next three hours.

Thoughts, suggestions, or experience?
 
Pilot Steve said:
I'd never had a GPS outage on my 430W until the planned GPS jamming testing this year. But now I'm having them more often in flight.

My avionics shop said they would replace the antenna first and check the connections but I'd love to hear from anyone else that has had a similar issue.

On my last flight, I lost the GPS data, regained it in 30 seconds or so, and then lost it again for another 30 seconds. After that, it was fine for the next three hours.

Thoughts, suggestions, or experience?
Click to expand...

Is it happening in one specific area you're flying over?

Are you transmitting on a comm radio when the symptoms appear?
 
121.5 ELT?
 
bnt83 said:
Is it happening in one specific area you're flying over?

Are you transmitting on a comm radio when the symptoms appear?
Click to expand...

This is what makes this so irritating. No and no. I do have a GPS outage at my home airport KRDU in the same spot on a taxiway but I've always had that.
 
There can be a number of sources of this loss of GPS. As bnt83 mentions, transmissions in certain frequencies can be one of them (via the transmitter harmonics itself or certain ELTs that can get triggered to reradiate) but that normally doesn’t just start happening. If this is happening in areas you usually fly and frequencies you normally use that hasn’t happened before, it could also potentially be a cracked antenna. The GA35 antennas are susceptible to cracking from over torquing the screws and then eventually start failing and one malfunctioning antenna can even take out a a second GPS receiver.
 
I had this issue with a 530 last year. Ended up being a bad part in the unit itself. But I would try changing your antenna first, that is the cheapest and easiest step.
 
Pilot Steve said:
That's my fear and I concur.
Click to expand...

For a flat fee, Garmin will repair everything that is wrong with a unit, so if you have any other issues, it might be a good time to send it back to them. I got a new screen, new radio card, and new GPS card out of them last year for $1500, or something like that.
 
I've had the same issue. Never had any GPS loss of signal in the last 10 years of flying and in the last 3 months, it's happened twice, to both my 530w and 430w at the same time. Signal came back within a minute or two. Very strange...
 
If you haven't had a concurrrent loss of nav in a portable GPS unit or tablet, a GPS outage is unlikely. More likely an antenna issue or a failure of a component in the GNS-430. I had a vertical guidance board failure in my GNS-430 about 10 years ago. One day, I couldn't get LPV integrity anymore. No error messages or other clues to what was going on, just a downgrade of every approach to LNAV only. Sent it back to Garmin for their fixed price repair, got a new vertical guidance board and a hard-wired "patch" to the main motherboard to fix a problem with that SN unit, plus a complete clean up of the exterior and a firmware update. Took about 2 weeks. Turnover was pretty good. I was even able to rent a loaner from them to keep flying. (Ironically, the loaner screen failed, and I got another loaner free of charge.)
 
Have an avionics shop look at it. Like other have said it can be a bad antenna or interference from the comm antenna. A quality Av shop can diagnose if the unit has a fault or an antenna is failing.
 
jkgoblue said:
I've had the same issue. Never had any GPS loss of signal in the last 10 years of flying and in the last 3 months, it's happened twice, to both my 530w and 430w at the same time. Signal came back within a minute or two. Very strange...
Click to expand...

It's nice to not be alone in this.
 
I had a E-04 406 ELT installed to correct a problem with my old 121.5 mHz ELT causing loss of GPS lock. It corrected the problem initially, but after about a year symptoms redeveloped. IAck asked me to check if the included static filter was attached to the base of the ELT antenna. It was not, and they told me to have it installed. I can't explain why a static filter would correct this problem, but it did. I've uploaded a copy of the Ack service notice on the need for this filter for static protection of the 121.5 circuit of its 406 ELT.
 

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bkspero said:
I can't explain why a static filter would correct this problem, but it did. I've uploaded a copy of the Ack service notice on the need for this filter for static protection of the 121.5 circuit of its 406 ELT.
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Interesting. This is why I love this forum. I'll have to check to see if it is installed.
 
If I were you, I would try a few more flights and see if it still acts up. Maybe someone you know has a 430w in their airplane, and you can swap units for a test.
 
Doug Reid said:
If I were you, I would try a few more flights and see if it still acts up. Maybe someone you know has a 430w in their airplane, and you can swap units for a test.
Click to expand...

It's one of those types of problems we all hate. It doesn't happen all the time. It will go weeks without happening. And there is no consistency as to why it happens. I flew a mission last night for three hours and not a single issue. Except for that darn freq flip button that doesn't like me much. LOL.
 
FYI, I was talking with a pilot friend earlier today and he was asking why his gps might be acting up. Seems he was doing approaches at KSCR, Siler City, which is only 35 east of KRDU only last week and had issues. So, there just might be a connection here ...I wonder if they might be jamming gps at the military bases here for war games .
 
Doug Reid said:
So, there just might be a connection here ...I wonder if they might be jamming gps at the military bases here for war games .
Click to expand...

It feels just like the outages I experienced during active jamming that was in the NOTAMs before but I just wish I could narrow it down before just dropping $$$ for a GPS antenna I might not need.

But that is an interesting observation. Thanks for letting me know.
 
I has seen several Garmin Waas antennae intermittently causing complete GPS lockup’s, all GPS’s including iPads.

Turn off one Garmin radio at time and see if it clears up. Have had it happen months apart. Had a 650/530/IPad combo Complete GPS failure and shutting down the 650 would get the 530 and iPad back, consistent over multiple tries. Next several legs of the long trip we’re fine. Had the same in a 430/iPad RV8 install.

Again very intermittent and a common problem that Garmin blames on overtorqued antennae mounting screws.

GM
 
I’ve had GPS outage on a few flights on my iPad Pro running ForeFlight over the last few months. Big red X for a few minutes, then Back up and running.
 
SOLUTION: Sort of, Maybe

I replaced the old GPS antenna and my problem went away. I can't say for certain that the antenna was the issue, or maybe a bad connection that was adjusted in the replacement. At least I don't have the issue anymore. For now. Fingers crossed.
 
I had an issue with my Narco MK12D radio killing the gps signal on my new garmin 175 gps at a local airport tower frequency. Would happen only at that airport, and on final when i was on tower...kinda of a bummer on final @ Instrument approach....My avionics guy figured it out, and added some kind of filter on the back of the radio to help. Evidently those radios were documented on specific frequencies to do that. I also just replaced my old (not working) TKM with a Garmin225 as my main COM1 now, and put the Narco as COM2/Nav1.
 
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