Losing GPS on approach

Any DA62 related topics

Moderators: Rick, Lance Murray

brian5x5
2 Diamonds Member
2 Diamonds Member
Posts: 13
Joined: Fri May 08, 2020 7:05 pm
First Name: Brian
Aircraft Type: DA62
Aircraft Registration: N1234
Airports: KEMT
Has thanked: 8 times
Been thanked: 3 times

Losing GPS on approach

Post by brian5x5 »

Has anyone experienced a loss of GPS in a DA62? I have been flying in a newly delivered plane and we have lost GPS several times while on approach (with approach loaded and activated). It always happens at around 2500 feet and clears itself up in about 40-70 seconds. We have just started to try to track it down and can't even tell if it is hardware or software related. One suggestion is to wipe out the G1000 NXi software and reinstall. This sounds like a bit of a pain considering they have pretty low confidence that it will help. Any ideas?

Thanks,
Brian
User avatar
Deanrobert
2 Diamonds Member
2 Diamonds Member
Posts: 45
Joined: Sun Jan 06, 2019 3:16 am
First Name: Dean
Aircraft Type: DA62
Aircraft Registration: N801VA
Airports: SPI
Has thanked: 6 times
Been thanked: 5 times

Re: Losing GPS on approach

Post by Deanrobert »

We had it happen in our 2017 da-62 , intermittently , when communicating on a frequency range between 121.0 and 121.3
Very strange. We had avionics shop check it out; thought the com antennas were two close ; all kinds of thoughts. It went away after our three year bonding check at annual. I was annoyed at the cost of checking all these grounding connections , but our gps approach issue kicking out stopped. So my take away is it has something to do with adequate , consistent grounding of the airplane…
brian5x5
2 Diamonds Member
2 Diamonds Member
Posts: 13
Joined: Fri May 08, 2020 7:05 pm
First Name: Brian
Aircraft Type: DA62
Aircraft Registration: N1234
Airports: KEMT
Has thanked: 8 times
Been thanked: 3 times

Re: Losing GPS on approach

Post by brian5x5 »

Interesting, KEMT tower is 121.2. That is where we usually experience it.
User avatar
mfdutra
4 Diamonds Member
4 Diamonds Member
Posts: 246
Joined: Mon Apr 26, 2021 10:49 pm
First Name: Marlon
Aircraft Type: DA62
Aircraft Registration: N272DD
Airports: KHWD
Has thanked: 206 times
Been thanked: 162 times

Re: Losing GPS on approach

Post by mfdutra »

I had this problem on my 2023 DA62. Diamond replaced the GPS-1 antenna and the problem was solved. Maybe it’s bad batch. I have the serial 53 from Canada.
User avatar
MarkA
3 Diamonds Member
3 Diamonds Member
Posts: 167
Joined: Mon Aug 23, 2010 4:58 am
First Name: Mark
Aircraft Type: DA40
Aircraft Registration: N123MZ
Airports: KHIO
Has thanked: 114 times
Been thanked: 133 times

Re: Losing GPS on approach

Post by MarkA »

Brian,

This sounds similar to a problem I and several other DA40 owners had earlier. You might want to check out the thread below where an intermittent hardware failure in one of the GPS antennas caused enough RF interference to block out the other antenna as well. The symptom was that the G1000 would intermittently loose contact with all satellites. The two GPS antennas sit right next to each other above the pilot's head on a DA40.

viewtopic.php?t=8252

Once the failing antenna was identified, the test to confirm that this was the issue was pull the circuit breaker on the GIA63 that was connected to the bad antenna and observe the satellites connecting through the good antenna. I've not seen any issues since the bad antenna was replaced.
2010 DA40 XLS, N123MZ, KHIO
https://youtu.be/LuQr6mGxffg
brian5x5
2 Diamonds Member
2 Diamonds Member
Posts: 13
Joined: Fri May 08, 2020 7:05 pm
First Name: Brian
Aircraft Type: DA62
Aircraft Registration: N1234
Airports: KEMT
Has thanked: 8 times
Been thanked: 3 times

Re: Losing GPS on approach

Post by brian5x5 »

Thank you Marlon and Mark,

These are super helpful for troubleshooting. It has been so intermittent that we can't get it to repeat on demand. These will give us some steps to try first. I will report back when we get to the bottom of it.

Brian
User avatar
haykinson
3 Diamonds Member
3 Diamonds Member
Posts: 114
Joined: Thu Apr 19, 2018 8:32 am
First Name: ilya
Aircraft Type: DA40NG
Aircraft Registration: N724LA
Airports: KSMO
Has thanked: 36 times
Been thanked: 48 times

Re: Losing GPS on approach

Post by haykinson »

Does it always happen in the same area? There are, for example, GPS anomalies that happen in the vicinity of KSMO — for years, I've lost ADS-B coverage due to a loss of GPS at around 1300 AGL, and even had full GPS loss during an approach (fortunately in visual conditions). The airport even had gone through a few weeks of having ATIS declare that GPS is unreliable after the latest bout of issues.
User avatar
MarkA
3 Diamonds Member
3 Diamonds Member
Posts: 167
Joined: Mon Aug 23, 2010 4:58 am
First Name: Mark
Aircraft Type: DA40
Aircraft Registration: N123MZ
Airports: KHIO
Has thanked: 114 times
Been thanked: 133 times

Re: Losing GPS on approach

Post by MarkA »

Note also that if the problem is caused by an intermittent failure of one of the GPS antennas, even when the antenna fails there's no indication of a hardware problem in the low-level G1000 error logs. The G1000 just thinks it lost contact with the satellites for some reason.

When diagnosing my issue, I did noticed the GPS signal strength reported on the G1000 AUX page for the intermittently failing antenna was consistently weaker than the good antenna. The failing antenna also reliably took longer to initially acquire the satellites. These are just hints for which antenna may be causing the problem.
2010 DA40 XLS, N123MZ, KHIO
https://youtu.be/LuQr6mGxffg
brian5x5
2 Diamonds Member
2 Diamonds Member
Posts: 13
Joined: Fri May 08, 2020 7:05 pm
First Name: Brian
Aircraft Type: DA62
Aircraft Registration: N1234
Airports: KEMT
Has thanked: 8 times
Been thanked: 3 times

Re: Losing GPS on approach

Post by brian5x5 »

haykinson wrote: Thu Jun 22, 2023 6:23 pm Does it always happen in the same area? There are, for example, GPS anomalies that happen in the vicinity of KSMO — for years, I've lost ADS-B coverage due to a loss of GPS at around 1300 AGL, and even had full GPS loss during an approach (fortunately in visual conditions). The airport even had gone through a few weeks of having ATIS declare that GPS is unreliable after the latest bout of issues.
No, it has been happening every flight now. From 13,000 feet in Northern California to short final in Salt Lake City and everywhere in between. It went in to the shop yesterday. I forwarded this thread so I hope that will help the diagnosis. I believe they are planing to replace GPS 1 and antenna. I will report back with the results.
User avatar
thommy152
3 Diamonds Member
3 Diamonds Member
Posts: 73
Joined: Sun Feb 20, 2022 12:22 am
First Name: Thomas
Aircraft Type: DA62
Aircraft Registration: N271CF
Airports: 16J
Has thanked: 71 times
Been thanked: 41 times

Re: Losing GPS on approach

Post by thommy152 »

I had a similar issues with the Garmin GTN650 in my 182. I replaced the GPS antenna and swapped out the GTN 650 but the problem persisted. It ended being a problem with the COAX cable to the GPS antenna. Once the COAX cable was replaced, the problem never happened again.
2000 C182S (N882SP) / 2023 DA-62 (N271CF).
Commercial ASEL, AMEL, CFI.
Post Reply