Lost my HSI (G1000) in IMC yesterday

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ThomasD
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Re: Lost my HSI (G1000) in IMC yesterday

Post by ThomasD »

This has happened to me as well, in solid IMC to near minimums, doing an ILS to an unfamiliar airport. The whole G1000 AI had a red X through it - no attitude, no LOC, no GS.
(I had passed my IR flight test just 1 week before - at least I was current in partial panel !)
Perhaps the least amusing thing was when I told the radar controller and he said "let me know if, I mean when, you get down".
The whole area was in IMC and there were no airports nearby so there was nowhere better.
Fortunately, the backup AI and altimeter were OK, as was the GPS, so I used these to work out a reasonably glide slope.
When I did get on the ground I powered off then on and it all came back as if nothing had happened.

After months of investigation it turned out to be poor crimps on the wires leading to the magnetometer (there are 3 or 4 connectors between the G1000 rack in the rear and the magnetometer. Very iffy connection, that varied with temperature.
It was found by an avionics guy simply pulling reasonably gently on the wires in turn at each connector. This was in the 4th avionics shop I took the plane to - but this 4th one did not do all the fancy diagnostics - they had the approach of "let's start with the simple things - it's often the connectors so let's physically look at them/try them and buzz out impedances of wires". Doing this they found the problem in less than an hour - whereas other avionics shops had spent literally weeks on re-calibration, measuring interference, measuring vibration etc.
Since then - never a problem again with this.

So I suggest start with the simple things - or tell your avionics shop to do so.

The AI and other things on the PFD went off as it seems that if the G1000 can't get something reasonable from the magnetometer it decides "I don't know what's going on so I will switch it all off" so no AI and you also lose the LOC and GS.
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Re: Lost my HSI (G1000) in IMC yesterday

Post by Antoine »

Thank you Steve, Bob Thomas (and Rick - see PM).

I think my problem is different to the one you reported Thomas although the experience was similar and my controller was MUCH better! You did a great job on your own apparently.You are right regarding the multiple connectors on the data path. and they are not easy to get to.
I only had the heading display "x" ed out. The rest was fine except for whatever info was derived from the heading such as... LOC.
Landing in IFR minima with "X" as your heading info and no LOC is not exactly a walk in the park. I had a fantastic approach controller and was very lucky to get heading working again just as we were intercepting the loc. I only realized how hairy it was when I saw the fire trucks escort us to the tarmac... and my passengers were making jokes during the landing...

Bob can you give me some more detail about th emessages you got ? I got NO error messages whatsoever.

I flew today (sunny) and was unable to recreate the problem despite shaking the plane and switching on off all combinations of lights... all OK.

So far the only corrective measure was removing the GMU and thoroughly cleaning the contacts with this miracle product from NY that was recommended by a fellow forum member Stabilant 22

I also checked that the drain hole that is below the G1000 rack is not obstructed - so nothing could have been flooded at this end at least...

It is going to be an annoying diagnosis I can tell.... I will try the recalibration and do a flight test on a wet day that is not too hard IMC. And annual is due this month...

Thanks again - will report back

A
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Re: Lost my HSI (G1000) in IMC yesterday

Post by csikes91 »

Jimmy and myself had the same type of issues when we bought 410FP. They swapped and tested and it ended up being the AHRS LRU. It was something that would happen on the ground and then come and go in flight. Glen was able to get to the bottom of it
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Re: Lost my HSI (G1000) in IMC yesterday

Post by BurdetteB »

I got no messages just the red X, at first was very intermittent then it would not come back at all once the ahrs memory chip was replaced the plane had to be put on jacks to enter the correct attiude this happened 2 years ago.
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Gary in TX
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Re: Lost my HSI (G1000) in IMC yesterday

Post by Gary in TX »

Interesting timing, Flying Magazine posted an article today that Garmin has recognized there is problem... I pasted it (couldn't get the link):

"In an FAA safety alert cautioning of temporary loss of heading and attitude display information in Garmin cockpits, the agency outlines steps Garmin has identified to prevent the issue from occurring.

The safety alert for operators (SAFO) is directed at airplanes equipped with the GRS 77/77H attitude heading reference system (AHRS) installed as a key component in the G1000, G900, G600 and G500 avionics systems.

Garmin continues to investigate the issue, which has been reported by a small number of pilots. The avionics maker thinks it may have traced the cause of the display loss to two factors:

1. Moving the aircraft on the ground during the first 10 seconds after turning on power to the AHRS.

2. Magnetic interference introduced near the magnetometers during AHRS initialization (i.e., during the 60 seconds following power up of the AHRS).

Either of these actions can cause "a noticeably drifting heading to be displayed on the PFD prior to takeoff, which may lead to a temporary loss of PFD displayed heading and/or attitude information after takeoff and during climb," Garmin notes.

As a preventative measure, pilots flying with affected gear are being advised not to move the aircraft on the ground during the first 10 seconds after turning on the pilot's and copilot's PFDs. Pilots should also not take off if the heading displayed on the PFD is noticeably drifting. When this occurs, powering down and reinitializing the AHRS normally resolves the condition, Garmin says.

Read more at http://www.flyingmag.com/avionics-gear/ ... HFQITx2.99"
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Re: Lost my HSI (G1000) in IMC yesterday

Post by Antoine »

Bob / Chris, thank you. Interesting that there may be an AHRS related cause.

Gary this is quite amazing. Not sure my plane has the same symptoms though (I only lose HDG, not attitude) and I don not think that my plane moves at all during power up (typically have my checklist in hand and going through cockpit related items.)

When I was in Norwich and the problem occurred, I taxied to the holding point and restarted the G1000 there. The problem happened again after that, so Garmin's fix did not work in this case.

Also, my problem has been appearing more and more frequently as if something was degrading...

go figure. I will tell my avionics guru about both infos though, thank you guys
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Re: Lost my HSI (G1000) in IMC yesterday

Post by ThomasD »

I have (regularly) had the red-X on the ground, in the circumstances described at point 2 by Garmin, i.e. where the aircraft was parked so that the right wing was close to a metal hangar door. However, I found that after taxiing away from the hangar the AI etc. always came back online within 60 seconds, and I have never experienced any AI drift.

Antoine: I must admit I would suspect a more substantial issue if this is happening more and more frequently and not in the circumstances described by Garmin. My original problem also degraded over time, due to a slightly marginal connection (I would guess) working very slightly more loose as time went on.

I expect that you know this, but if I was having problems like this again I think I would:
- when you get a red X, check the AUX page to see which LRUs are reporting a failure (scroll down to see the full list)
- re-seat all G1000 LRUs
- then get all the wiring and connectors checked (pull test and buzz out impedance)
- then get the individual LRUs checked for correct inputs/outputs & within spec/swapped out
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Re: Lost my HSI (G1000) in IMC yesterday

Post by tjgoddard »

I had the same issue in our DA40 S/N 40.444. We finally found the common denominator. Each time this occurred a "smart phone" was in the back seat (right above the AHRS). This did not happen every time a smart phone was in the airplane, but every time it happened someone had their phone "on". Placing all devices on "airplane mode" has solved our issues with no occurrence for at least a year.
On a customers aircraft that we maintain having long range fuel, the magnetometer is in the same location as on the standard fuel models. This places it very close to the added fuel tank and it's associated capacitance fuel level wiring. This customer will have issues when fuel level is full and never with reduced fuel. Diamond has a SB to move the magnetometer toward the wingtip to fix the issue but only for the diesel models (go figure). The newer models all have the magnetometer located closer to the tip and away from the fuel tank.
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Re: Lost my HSI (G1000) in IMC yesterday

Post by Steven M »

Just came across this forum. Four years late in commenting may not assist anyone, but I had intermittent HSI red-X'ing for about 2 years while trying to find a fix. Without giving all the intermittent fixes attempted by my avionics and maintenance people such as re-loading software and deguizing the counter-weight on the aileron near the magnetometer, the fix was accomplished by relocating the magnetometer about a foot further out in the wing. Diamond has a bracket to do just that. I've had no problems in two years now. As for protecting against it, I found that by superimposing a magnetic heading on my MFD and extending the trend vector to pass through it I was able to fly vectors assigned by ATC without having to use the compass (which is poorly installed for use from the left seat).
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