LX 9070 disoriented

[Joaquim Fonseca]

Hi,

Today I flew across France and towards the end of the trip my LX9070 got disoriented a few times. The heading that it was showing, and the glider path were completely wrong. Luckily I have a good sense of orientation and did not trust it and continued my flight path after confirming in my iPhone with Skydemon. If I trusted the LX, one of the occasions I would have flown in restricted airspace.

Has this ever happened to anyone? It's new, so there is no reason to start failing.

Thanks,

Joaquim 

[Morgan Hall]

I am suspicious of the latest firmware.  I had major issues with bizarre winds and behaviors like jumpy or incorrect track and heading and unreliable hawk.  

I reported my issues to Uros and he found a lot of dropouts in my GPS data.  I pulled the canopy and glareshield off and found a loose gps antenna on the LX.  Really hoped that was the culprit, but my last flight still had very unreliable Hawk performance, although none of the crazy winds.  

I am left feeling like something is off with recent firmware.  Could be wrong, but this has happened before where some update causes Hawk to fail a lot.  

I haven’t sent my latest log to Uros to see if there are still GPS dropouts.  I am going to see if I can determine that one my own, but I know that at least my antenna cable is snug.  

It’s not unusable as an instrument, but the Hawk is trending towards negative value every time it starts to misbehave like this.  

Morgan

On Sat, Jul 5, 2025 at 12:51 Joaquim Fonseca <jjofo...@gmail.com> wrote:

Hi,

Today I flew across France and towards the end of the trip my LX9070t got disoriented a few times. The heading that it was showing, and the glider path were completely wrong. Luckily I have a good sense of orientation and did not trust it and continued my flight path after confirming in my iPhone with Skydemon. If I trusted the LX, one of the occasions I would have flown in restricted airspace.

Has this ever happened to anyone? It's new, so there is no reason to start failing.

Thanks,

Joaquim 

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[Marc Arnold]

Morgan

Yes — I had very unusual LX9070 behavior today. Normally, it is absolutely rock solid. About two hours into the flight GPS went away and did not come back until after landing. I have never seen this before.

I’ve also never had difficulty with OLC upload, but today the OLC option disappeared from the Save screen and was greyed out on the Services screen. Strange. 

Still getting used to HAWK, but so far so good. Seems like a valuable addition. 

Marc Arnold

Longmont CO

On Jul 5, 2025, at 2:35 PM, Morgan Hall <mor...@gmail.com> wrote:



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[John Johnson]

Marc,

I'd guess the OLC upload is a separate issue - the OLC site itself has been a bit flaky lately and I've seen both direct web access and LX connect access drop out a few times.

Not sure this applies in your case, but in southern Arizona, I've occasionally seen GPS dropouts due to interference testing out of Yuma (military restricted airspace).  Usually, these testing periods are short and 'off-hours' (ex: 0100-0300 local) but sometimes they occur in the afternoon.  The FAA safety site ("FAASTeam") lets you subscribe to receive notices of upcoming testing.  White Sands is common interference testing site and I recently received this notice as an example:

FLIGHT ADVISORY - GPS Interference Testing – White Sands Missile Range, NM
Notice Number: NOTC4482

FLIGHT ADVISORY

GPS INTERFERENCE TESTING 

WHITE SANDS MISSILE RANGE NEW MEXICO

(WSMRNM) 25-10 

02 – 19 July

White Sands Missile Range, NM 

Centered at   333753N1063234W or the TCS047042 

The entire flight advisory may be accessed and downloaded at the following address:

https://www.faasafety.gov/files/notices/2025/Jun/WSMRNM_25-10_GPS_Flight_Advisory.pdf

 

JJ

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[Marc Arnold]

Yes—GPS and hot spot connectivity seem unrelated…unless it’s a firmware update problem. 

On Jul 5, 2025, at 3:24 PM, John Johnson <john...@gmail.com> wrote:



[Spichtig Joerg]

I experiences  the same after installing V9.51 in April 2025. This was also the case with the BETA version end of last year after V9.07 when the Hi-speed data bus mode was introduced. I had regular GPS failure every flight which could only be cured by restatring the whole system. I reported this to LXNAV but I got only the answer, that I need to rearrange (or replace) the GPS antenna. Interestingly, after reverting to V9.07, the problem disappeared again. I fly a twin  seat configuration with LX9070/LX9000D GEN4 with attached V8/S8.

 

Joerg

 

Jörg Spichtig
Dipl. Ing. ETH
Managing Director
AeroFEM GmbH
Aumühlestrasse 10
CH-6373 Ennetbürgen
jspi...@aerofem.com

www.aerofem.com

Office: +41 41 619 85 01
Mobile: +41 79 286 91 32

EASA DOA 21J.644

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[Joaquim Fonseca]

I contacted LXNav and their reply seems logical: "the problem was in the HAWK algorithm when running on an engine. HAWK was designed for soaring performance. When running on an engine, there are additional vibrations from the engine that affect the HAWK algorithm.

Because of this wind calculation was completely off and this gives you wrong orientation as calculated heading was not ok.

I suggest you switch off HAWK, when running on the engine."

I will keep Hawk on and turn it off when it gets disoriented to see if it solves the issue. In my case it's a new installation with the GPS antenna in the same place it has been for the last 15 years with the old LX9000.

[Jeff Stetson]

My Ximango, with its 4-cylinder Rotax 912S engine, runs quite smoothly and doesn't seem to disturb HAWK all that much. Numbers like Netto are way off of course, but things like horizontal wind are quite reasonable. The S100/HAWK when thermaling with a bit of engine power seems to work right too, once one understands the "zero" on the vario is offset by added power. The condition it doesn't seem to like though is circling when the real climb or decent per orbit is near zero. In this state HAWK gives much larger than real indications. Re-setting via the panel button doesn't change this.

GPS signal interruptions and worse, spoofing, are getting to be a serious problem, even in areas away from MOA's and military bases. Many are brief, and often not noticed in flight, but are quite visible in tracklogs afterwards. One in-flight clue on my iPad/Foreflight/Sentry setup is getting terrain collision warnings many thousands of feet agl.

Another way to potentially mess up GPS reception is to have antennas of multiple devices too close to one another. Garmin states:  “A 12 inch center-to-center spacing between GPS antennas is required to achieve the best possible low-elevation antenna gain by minimizing pattern degradation due to shadowing and near-field interaction….Spacing less than 9 inches center-to-center results in unacceptable antenna pattern degradation.”

So even in my wide cockpit, that's not so easy to do, with phone, iPad, Sentry, Oudie and LXnav antennas in play. Not to mention VHF, FLARM, transponder, and TIS-B antennas in play. Moving things around might help.