Garmin 1000 GPS failure in flight

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DCLEMONS
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Garmin 1000 GPS failure in flight

Post by DCLEMONS »

Good morning !
I was flying yesterday cross county, 5 hours. Alert message GPS NAV Lost , insufficient satellites. I checked the SATS 1 and 2 both were completely gone. What are the chances of both GPS units failing at the same time?
4 months ago Garmin swapped out GPS 1 for $1,000.00

ALERT - AHRS 1 GPS - AHRS 1 using backup source.

ALERT - AHRS 1 GPS - AHRS operating exclusively in NO -GPS Mode


ALERT - GPS NAV LOST - Loss of GPS navigation - insufficient Satellites.

This all happened over an hour of time- I was surprised to see both GPS both fail.

5 minutes before landing the GPS ( BOTH ) come back on line. Is any one experiencing the same issues?
Can you share with all of us what were the actual fixes , replacements and trouble shooting. I m frustrated that the Garmin is not as reliable as I feel it should be.

Any help here with fellow DA40 owners would help here. Thank you ! :!:

PS - I searched for Garmin failure, but the search on this site can not find this combo of words.
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Re: Garmin 1000 GPS failure in flight

Post by CFIDave »

Before trying anything else, spend 15 minutes to make sure your G1000 isn't suffering from bad/intermittent electrical contacts:

1. Pull up the carpet of the rear baggage compartment and open the access panel in the floor that's held in place with just a few screws. This will expose the equipment rack where most of your G1000 Line Replaceable Units (LRUs) are located.
2. Remove all of the LRUs, by removing one screw on the top of each and then pulling each LRU straight up out of the equipment rack (like toast in a toaster).
3. Spray electrical contact cleaner all over the bottom of the (now empty) equipment rack, cleaning the electrical contacts where the LRUs plug into the rack.
4. Put it all back together.

I can't guarantee this will fix your problem, but I've seen it fix issues like G1000 bus errors and some intermittent outages.

(Another thought: are you sure the US military wasn't conducting one of its many GPS outage tests? These routinely wipe out GPS reception across large areas.)
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DCLEMONS
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Re: Garmin 1000 GPS failure in flight

Post by DCLEMONS »

Hello Dave,
Thank you for your comment. I will do that today - can you recommend a contact cleaner? I did fly through a non-active MOA yesterday - and I thought the same thing...but after flying outside for over 50 miles it would seem the GPS would have engaged. Its confusing to me :)

These are great steps to follow - I also contacted Dave Potter of Black Mountain Avionics to see what he thinks. Ill let you know the outcome.

Again appreciate and VALUE this help !

David
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Re: Garmin 1000 GPS failure in flight

Post by trepine »

Just curious if you tried to reboot the garmin in-flight.
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Re: Garmin 1000 GPS failure in flight

Post by carym »

Dave,
With both GPS units showing no satellites, this sounds to me that you were hit with military disabling of the GPS satellites. It would be very unusual, indeed, to have both GPS units go out since they use separate antennae and separate LRUs. Did you happen to look for any NOTAMs that showed GPS testing in the area?
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Re: Garmin 1000 GPS failure in flight

Post by DCLEMONS »

I didn't reboot my Garmins... do mean pull the CB?
I should have thought of that ....
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Re: Garmin 1000 GPS failure in flight

Post by waynemcc999 »

When flying the C162 Skycatcher I had frequent "red Xs" from the G3X (small screen equiv of the G1000). Short term fix during flight was to cycle avionics off/on (even do it preemptively before takeoff/landing). Successful permanent fix, as Dave suggested, was to clean all the connections.
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Re: Garmin 1000 GPS failure in flight

Post by CharlesMc »

David,

It happened to me a couple of years ago, required the replacement of both antenna pucks by Garmin. One antenna will short out, jamming the other, and if you have a handheld back up inside the cabin, jams that as well.

This is / was a known issue affecting a certain serial number range of pucks.

I posted my experiences and resolution here, searching on my user name may help.

Charlie
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Re: Garmin 1000 GPS failure in flight

Post by DCLEMONS »

Thanks to everyone who is sharing knowledge here. The military MOA region NE of Las Vegas, might have been active but I could not establish radio contact with them , with the frequency found in Fore Flight, published on the map.

My Garman 1000 tech stated that both antennas had hairline cracks in each of the 4 screw hole areas. It required a specialized headset to see the fractures , very obvious with the zoom glasses on. We have ordered a replacement from a Garmin supplier.

I believe this must be at least part of the issue. ( The hit line cracks ) On the ground and early in flight the equipment has always worked. But after flight and up to 12,500 I believe moisture , pressure and possible cross candle is going to prove the issue for GPS failure. Ill keep you posted.

We have ordered the antennas and should have them in this next week for a test flight.
Thx!

David
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Re: Garmin 1000 GPS failure in flight

Post by rwtucker »

On the "reboot" diagnosis: High probability of being correct. The G1000 is Windows NT. It is a very solid kernel; however, the drivers are written by Garmin and not all of them as as solid.

On the exogenous interference diagnosis: Possible. This is a longer discussion but GPS jamming and, more often, misdirection experiments are more common in NV than those for which NOTAMS are issued. I can confirm this based on multiple experiences. In addition, the impact zone is almost always larger than the NOTAM specifies.

On the "bad contact" diagnosis. More possible. Many DAN members have reported this problem. In theory, all you need to do is remove and (gently & precisely) replace each LRU. The gold wipers are thin. You don't want to put deep scratches into them. You could spray Radio Shack contact cleaner on them but I do not recommend it. Gold does not oxidize and the rapid contraction from the -120 degrees could cause a problem. Some DAN users and other pilots and avionics gurus swear by Stabilant 22. I would try it if your R&R fixes the problem and it then recurs. Stabilant 22 is purported to increase the quality of the contact (i.e., lower resistance, less DC chatter).

On the "hairline crack" diagnosis: I doubt it and I would not replace the antennas. There isn't usually much moisture at 12,500 but more importantly, the cracks you see have nothing to do with the antenna electronics.

My best guess alternate diagnosis: Your Garmin guys who charged you $1,000 to replace a module screwed something up.
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