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G3x with gsa 28 autopilot

L

ljpgrif

Member
Has anyone had a problem with the autopilot where its on and it disengages at random..... alarms...then the ap..pitch..roll shows all X's?

Coming back home and ap..fd...nav...vs 500 ft/down from 6500 ft to 3000 ft. Clouds was near so decided to change from nav to heading. With ap still on..changed heading 30 deg right....after about minute....ap disengaged...alarms and all X's.
Pushed the external disengage button....the all the X's disappeared.
I then went to g3x screen for the ap bar then pushed the fd button...worked at that point. Never tried the ap anymore that day.

Could it been a hardware problem or a pilot error input?

Larry Griffin
N687VR
 
Just a thought.

Larry, I hope you record data during your flights - - - if so go back and study the AP data. It has mode, torque, trim etc for what AP - - it may well give you some better insight - - or you could send the whole file to G3Xpert too. I like to do that for better understanding, so you can do both.

I have solved several issues this way - some set-up, some pilot, none yet the AP.
 
Kinda sounds like a CAN bus problem, the AP is less fault tolerant than the other LRU's.
Take a look at the bus on the config menu, anything other than '0' is a problem.
There is also an advanced method to look at the bus, take a look in the manual under CAN bus troubleshooting.
 
G3x ap

Bill...my G3x is setup to record each flight....love that feature...called garmin support and they want me to send the flight data file to determine the problem.

Walt....you say to go on conf menu...ap section and see what the can data shows?
What should I see....anything except zeros?
Once had a oil temp showing going up from 185 to 220f.....replaced sensor but ended up to be a loose wire.
Wonder if that could be the problem.
I'll check it out this weekend...

Thanks for the input...
Larry
 
ljpgrif said:
Walt....you say to go on conf menu...ap section and see what the can data shows?
What should I see....anything except zeros?
Once had a oil temp showing going up from 185 to 220f.....replaced sensor but ended up to be a loose wire.
Wonder if that could be the problem.
I'll check it out this weekend...

Thanks for the input...
Larry
Click to expand...

Config-System shows each of the LRU's, scroll to GSA28 and you'll see "CAN bus error" anything other than 0 is bad.
CAN bus troubleshooting PDF below.
You can look at each LRU as well.
In the manual: 2.3.1.3.6 CAN Bus Troubleshooting
Garmin troubleshooting guide is below.
 

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The G3x can be sensitive to button pressing. I think if you hit the trim button, it will disengage. This has happened to me a few times and it was because I touched something. Also, is your torque setting high enough?
 
lr172 said:
The G3x can be sensitive to button pressing. I think if you hit the trim button, it will disengage. This has happened to me a few times and it was because I touched something. Also, is your torque setting high enough?
Click to expand...

Torque settings or inadvertent disconnect will not cause the AP to X out.
 
Let us know what the garmin folks come back with. They are the most likely to give you useful results as they will investigate the log file and see the errors, etc.
 
G3x ap

I'm leaning toward a loose wire problem. When you power up the g3x and forget to turn on the com power switch....you see the com X just like my ap X problem.
I have powered up the g3x and tested the ap and its works fine now....I've not done anything to it!
I believe its wire tracing time......the builder believed in wire crimping not soldering.

Thanks again everyone....when I find it...I'll
let y'all know.

Larry
 
AP Disconnect

ljpgrif said:
I'm leaning toward a loose wire problem. When you power up the g3x and forget to turn on the com power switch....you see the com X just like my ap X problem.
I have powered up the g3x and tested the ap and its works fine now....I've not done anything to it!
I believe its wire tracing time......the builder believed in wire crimping not soldering.

Thanks again everyone....when I find it...I'll
let y'all know.

Larry
Click to expand...

Larry,

Send us the 1 Hz log from the flight in question when you get a chance, we log a lot of information related to events like this, we can likely help narrow down the cause of the disconnect, and get you pointed in the right direction.

Thanks,

Justin
 
G3x ap

Emailed the flight log and all the conf -system info to Garmin to see why it faulted and showed all X's in flight.
Garmin emailed me back and recommend to update the g3x gdu from 6.30 to the latest 8.81.
I have reservations on updating a random problem when all original equipment has been working fine for 3 years.
This problem will surface again and when it fails completely.....I'll know then.

Larry
N687VR
 
This isn’t an unreasonable response, there are lots of improvements in newer code that handle can error, etc. Garmin doesn’t publish a support lifecycle for their versions but it’s not uncommon for IT shops to only support a few versions back from current and require customers to update for support.

On the plus side you’ll see a huge number of new features considering it was running such an old version.
 
G3x ap

After troubleshooting and found no wiring problem, sent a copy of the log file to Garmin. Garmin Tech wrote back and said that if I update the firmware to current, version 8.91, it will fix the problem. Last week I updated to 8.81 but now its time to update again......

Larry
 
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