Grt Panel help

Installed a grt ws dual panel and love the way it looks. I?ve had it installed for over a year before getting the first flight. Everything aligns and comes up, but I?ve lost ahrs info on initial flight and the last 4 test flights, and 1/2 doz taxi test. Problem is, it isn?t consistent when it stops providing airspeed and altitude. Checked all grounds, checked all pins in connectors.Mark from grt sent me another ahrs, same results. I haven?t checked the magnatomer and since it aligned and came up with ?blue screen? I never calibrated the mag and ahrs. I?m sort of out of possible remedies other than completely starting over and building new harnesses. Any suggestions?
Mike

It seems highly likely to be a wiring issue - an intermittant connection somewhere. These are the worst to troubleshoot. On the ground, see if you can make it fail by gently tugging, one at a time, on the wires between the efis and the adhrs box.

BobTurner said:

It seems highly likely to be a wiring issue - an intermittant connection somewhere. These are the worst to troubleshoot. On the ground, see if you can make it fail by gently tugging, one at a time, on the wires between the efis and the adhrs box.

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The good news is that is not that many wires you need to tug!

Still searching update

Trying through process of elimination. I?ve check ?all? wiring and connections. Removed one screen. Tried to calibrate the magnetometer and is failing. Hope this is my problem. Removed wingtip and checked to make sure ?all? connections and wires are correctly pinned and conducting properly. No Metal around mag. May try to relocate magnetometer or wait on grt response.

I would suggest picking up the phone and calling GRT while you are at your plane. They are fantastic people to work with. Give them a call.

Grt

We had a 10:00 call in plan to do that but they were out till Monday

RepmikeBrown said:

We had a 10:00 call in plan to do that but they were out till Monday

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Yes, being a small company, they close the office at noon on Fridays and have a company BBQ. I know if you call them on Monday you will be talking with someone who will help you.

Magnetometer

Don't rule out the magnetometer. It's info is critical to the AHARS attitude solution. If you haven't calibrated it, if it isn't accurately aligned to the aircraft yaw, roll, and pitch attitudes, or if something induces magnetic interference to it you will have issues with attitude. I don't thing the AHARS will even provide attitude information without a functioning magnetometer.

Skylor

Mag

Swapping one out this morning
Thanks

RepmikeBrown said:

Trying through process of elimination. I’ve check “all” wiring and connections. Removed one screen. Tried to calibrate the magnetometer and is failing. Hope this is my problem. Removed wingtip and checked to make sure “all” connections and wires are correctly pinned and conducting properly. No Metal around mag. May try to relocate magnetometer or wait on grt response.

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I have had several magnetometer issues with my GRT, including a bad connection. Through all of it, I NEVER had the AHRS fail to poperly communicat and present good data on my HXr, except the heading, of course.

I doubt the magnetometer is causing your problems.

Larry

skylor said:

Don't rule out the magnetometer. It's info is critical to the AHARS attitude solution. If you haven't calibrated it, if it isn't accurately aligned to the aircraft yaw, roll, and pitch attitudes, or if something induces magnetic interference to it you will have issues with attitude. I don't thing the AHARS will even provide attitude information without a functioning magnetometer.

Skylor

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This is not accurate, at least for the GRT. I have had my mag fail as well as flown it uncalibrated. Attitude is rock solid. Calibration is irrelevant. Reported heading relative to true north has absolutely no bearing on attitude calculation, as the AHRS has no idea what true north is, only what the mag reports. Yes, erratic heading changes from a broken mag I imagine can cause minor issues, but unlikely it will override the accelerometers that are relied upon for attitude. I would be highly disappointed if my EFIS is using magnetic input to determine the attitude of my plane. Sure, it may assist in smoothing out the data for a good presentation, but not relied upon. Further, the GRT will switch to GPS track if the magnetic heading fails and I suspect also if it becomes untrustworthy. I do trust backup devices that leverage GPS track in determining attitude, such as my 396, but that is only for emergencies and it is my 3rd backup.

Larry

I agree with Larry. I have had a magnetometer failure and the only thing affected was heading accuracy. You do need to make sure the magnetometer is aligned with the AHARS for accurate heading information but the failure of the magnetometer will not cause the other issues your experiencing.

I strongly suspect your problem is an intermittent wiring connection problem between the AHARS and the EFIS.

Grt help

Can?t say enough about Mark and GRT getting me going. Talked with Mark for less than 2 min.
He had my issue resolved. I had one wire and pin out going to the wrong screen. These guys are the best.
Mike