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GFC500 Yaw Damper Squawk - Long Body


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About two months ago, I had a GFC500 with the Yaw Damper option installed in my Bravo.  I occasionally the autopilot has an "adverse disconnect" initiated by the yaw damper servo.  I talked with the shop about the issue and they recommended that I insure that I am:

1.  adjusting rudder trim properly.

2. avoiding resting my feet on the rudder pedals.

I am indeed doing these two things and yet I am still having the issue.  In fact, when I transition from climb to cruise, I disengage the yaw damper, verify the rudder trim centers the indicator, then I re-engage the yaw damper just to be sure.

Data logs are downloaded and will be sent to the shop on Monday and then to Garmin for review.  Has anyone else seen this issue?  What do you think the RC is?

 

Alex

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Let’s see if @donkaye is around today... (Bravo, GFC500, yaw damper challenge...)

There was an early discussion about servos fighting with sticky controls...

Wondering if there is a way to clean the rudder controls from one end to the other to improve on this...

PP thoughts only, not a mechanic...

Best regards,

-a-

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Never for my YD and my K doesn’t have rudder trim so it’s always “working hard” in climbs.  I did have a very intermittent issue with my pitch trim and it was replaced, there was supposedly a troublesome batch of Servos out there. I’ve had No issues after the servo was replaced. 

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43 minutes ago, 81X said:

Never for my YD and my K doesn’t have rudder trim so it’s always “working hard” in climbs.  I did have a very intermittent issue with my pitch trim and it was replaced, there was supposedly a troublesome batch of Servos out there. I’ve had No issues after the servo was replaced. 

Thanks, that helps me frame an expectation.  The data logs have been delivered to Garmin...waiting for a response.

 

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  • 8 months later...
On 2/9/2021 at 8:37 PM, alextstone said:

Thanks, that helps me frame an expectation.  The data logs have been delivered to Garmin...waiting for a response.

Any update or resolution?   (I'm deciding whether a YD make sense for my short body E. ) 

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Any update or resolution?   (I'm deciding whether a YD make sense for my short body E. ) 
Yes. Replaced yaw servo and lubed the control rod ends. Also needed to pay careful attention to adjusting the rudder trim with every change in phase of flight.

Sent from my Pixel 5a using Tapatalk

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Don't spend too much time chasing ghosts (like I did for 9 months) before your shop determines if the servo is defective.  Everyone said "it must be your yoke is sticking" or "has to be the pitot static system" when it was just shitty servos from Garmin.  I had my Pitch and Roll servo replaced and I'm told it's now extremely common to have defective servos on the GFC500.  The way they found out mine were defective was that the clutch would violently release rather than let you apply smooth controls with the yoke.  I'm not sure how you can test this on the ground with the yaw one (maybe try to make opposite rudder movements to turns? althought this may be limited since your nose wheel is on the ground) but your shop may have some ideas.

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23 hours ago, alextstone said:

Also needed to pay careful attention to adjusting the rudder trim with every change in phase of flight.
 

I wish the YD didn't come on automatically when I put on the AP. I think I need to look in the maintenance manual and find out what the correct "center" for the rudder trim is on the indicator and tail position. I would assume that the tail is centered in cruise flight but I have been known to be wrong (about a lot of things depending on who you ask).

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15 minutes ago, PilotX said:

I wish the YD didn't come on automatically when I put on the AP. I think I need to look in the maintenance manual and find out what the correct "center" for the rudder trim is on the indicator and tail position. I would assume that the tail is centered in cruise flight but I have been known to be wrong (about a lot of things depending on who you ask).


Two ways to know when the rudder is centered properly…

1) on the ground… Set rudder trim to follow the yellow taxi stripe on the ground…

2) in the air… Set rudder trim to center the ball while in level flight…

3) This takes into account that there is physical tail rigging settings to fly straight… with our right rotating prop…

Expect variations with weight loading from right to left…. And attitude from front to back…

While climbing and descending in smooth air… you can really see the affects of aviation’s laws of physics… just like the aviation 101 book says.

PP thoughts only, not a cfi…

Best regards,

-a-

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16 hours ago, carusoam said:


Two ways to know when the rudder is centered properly…

Thank you sir. I looked up the procedure in the maint. manual after I made that comment. Then I went to sleep and flew down to Riverside California today. I love the Bravo. The YD didn't disconnect at all. Just needs to be a checklist item when transition from climb to cruise flight.

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