Data Path Failure

Any DA42 related topics.

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Rick
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Re: Data Path Failure

Post by Rick »

I have gotten an AFCS warning a couple of times (red warning in the upper left of the PFD), and I have always been able to clear it by cycling the AFCS breaker - it's on the bottom row somewhere. If you ever see this gremlin again, that is the first thing I would try. You can reset it in flight without disrupting anything except for the autopilot.

By the way, this is the same CB you would want to pull if you had a trim runaway (which I've never heard of on a Diamond) - I have mine marked with a red plastic collar for quick identification just in case!
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Re: Data Path Failure

Post by CFIDave »

dmloftus wrote: Wed Jun 02, 2021 3:45 pm I appreciate the info in this thread and would love to know if anyone else has had a similar experience.
As noted here in this and many other threads, a Data Path failure error is often caused by dirty contacts in the G1000 equipment rack under the rear baggage compartment. With a Lycoming DA40 It's about a 15 minute job to fix with contact cleaner.
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Don
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Re: Data Path Failure

Post by Don »

I am currently going through the "Data Path" issue. After booting up, I get that message and then "Roll" in a red block which appears in the upper left of the PFD screen. The autopilot and FD will then not engage. The Garmin shop on my field diagnosed it yesterday as a bad roll servo. Fortunately, the servo is very easy to get to and as it is located just under the right rear seat through the access hatch and the servo only requires removal of two bolts. We ordered a rebuilt exchange servo from Garmin yesterday at a cost of $1300 and should be here Friday or Monday at the latest. I am keeping my fingers crossed that it fixes the problem.
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Re: Data Path Failure

Post by dmloftus »

CFIDave wrote: Mon Mar 11, 2013 3:36 pm You should see a big silver box (equipment rack), which I assume is the same in the DA42 as in our DA40.

Inside the box is a set of G1000 Line Replaceable Units (LRU electronics modules) that each can be pulled straight up once you remove one screw at the top.

After removing the LRUs, spray electrical contact cleaner into the bottom of the equipment rack.

Here's a better picture of the G1000 equipment rack (from a DA40), with the entire floor and rear baggage compartment removed.
Hi Dave,
I encountered another data path failure message this week on startup. At the runup area I tried to cycle the Avionics bus (which had cleared the error inflight a week ago) but that did not clear the error. So I shut everything down and restarted and it was fine. After returning to my hangar, I pulled the rear floor to see if I could remove and reinsert the LRUs in the avionics rack. Where is the "screw at the top" you mention that needs to be removed? I could not see any screws holding the lips of the aluminum casings to the chassis. I know there must be some kind of retaining mechanism to keep them seated, but it looks visually like you could just pull them straight up. I tried gently lifting at the edges but they didn't budge. Which LRU's are actually in this rack? The only LRU's labeled at the top are 2 GIA63W's and each of them seem to be strapped across the top to an adjacent LRU, and the GDL69A. Is it one single screw for the entire chassis as you mentioned in your 2013 post or do you need to remove each of the screws from those straps? I note four screws in your picture from 2013, mine only has three, the difference being my front-most LRU (with blue Garmin sticker) has no screw visible on top. Do you lift from the horizontal lips that extend over the edges of the chassis or are you lifting the LRU out of those sub units?

Also, is there a brand of electronics cleaner you would recommend? Legally do I need an A&P to do this or can this be considered minor maintenance since I'm not really doing anything to the units? Thanks

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Re: Data Path Failure

Post by CFIDave »

It's been so long (I haven't owned a DA40 for 8 years) since I posted those pictures and instructions, but I recall that there's one screw per LRU (as can been seen in your photo for 3 of the 4 LRUs.) You remove the screws and associated straps, and then each the LRUs individually pulls straight up out of the equipment rack. I had an A&P show me this procedure using just a screwdriver and can of contact cleaner.

I don't have a recommendation for a specific brand of electrical contact cleaner. And no need for an A&P signoff -- you're not modifying anything.
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Re: Data Path Failure

Post by arksat »

David,

Actually the GIA has a lift handle that looks like a metal strap.
You can remove the screw on the handle, and pull the handle up to remove the unit.

Be careful, do this gently especially when re-installing the unit.
The connector pins are so thin and very easy to get damaged.
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Re: Data Path Failure

Post by dmloftus »

arksat wrote: Sun Jun 20, 2021 3:48 pm David,

Actually the GIA has a lift handle that looks like a metal strap.
You can remove the screw on the handle, and pull the handle up to remove the unit.

Be careful, do this gently especially when re-installing the unit.
The connector pins are so thin and very easy to get damaged.
Thanks Dave and Tosh, very helpful. Any idea what the LRU is with the blue Garmin sticker? It looks to have no top retaining screw or handle. Just a flimsy little black plastic tab that is spring-loaded. It doesn't seem substantial enough to pull an LRU upward out of the chassis. Is this the air data computer? Any idea how to safely remove/replace it with no handle? Thanks again.
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Re: Data Path Failure

Post by CFIDave »

The unit with the blue sticker appears to be your transponder. Not sure how it's held into the rack, but you can probably figure it out after removing the pair of GIAs next to it.
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Re: Data Path Failure

Post by dmloftus »

CFIDave wrote: Sun Jun 20, 2021 6:42 pm The unit with the blue sticker appears to be your transponder. Not sure how it's held into the rack, but you can probably figure it out after removing the pair of GIAs next to it.
Yup, been doing a bunch of Google searches. Looks like that is my GTX345. Reading through G1000/GFC700 System Maintenance Manuals now. Reminds me of my old days 30 years ago as a design engineer for F15 APG63 radar and F16 ALR69 Radar Warning Receivers. Thanks.
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Re: Data Path Failure

Post by dmloftus »

BTW, there is a Garmin Service Advisory on this exact issue. I am getting the messages "FAILED PATH – A data path has failed" and "AHRS 1 not receiving backup GPS information". And the AFCS warning annunciator in the upper left of the PFD. How can you have a partial failure (and all green checkmarks on the AUX page) that disappears when you cycle power??

https://www.garmin.com/en-US/aviational ... a-failure/

Service Advisory 1518: Partial GIA Failure
MARCH 3, 2015 SERVICE ADVISORIES
AFFECTED PRODUCTS:
G900X, G1000, Cirrus Perspective, Embraer Prodigy, G2000, and G3000 systems with a GFC 700 (GFC 7X for G900X systems) and GIA main software version 7.60 are affected.

ISSUE:
One or both GIAs may lose certain functionality upon power-up and result in the presence of one or more of the following failure indications:

A system message indicating “FAILED PATH – A data path has failed.”
A system message indicating “AHRS 1 GPS – AHRS 1 not receiving any GPS information” or “AHRS 2 GPS – AHRS 2 not receiving any GPS information.”
A red AFCS annunciator indicating the Pre-Flight test has failed and the GFC 700 is not available.
A CAS alert indicating “ESP Fail.”
Other miscellaneous CAS messages, depending on system configuration.
NOTE

Under normal circumstances, some of the indications listed above may be visible for a short amount of time during power-up.

PILOT ACTION:
Do not depart if these indications persist. Contact your local Garmin dealer.
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