67 F Trim Issue- Quick Question

[MrRodgers]

Hi everyone,

My trim indicator was not working on run up today.  I parked the plane and looked at the issue.  The trim wheel turns freely but the tail section does not move at all to retrim the airplane.

After further review, mechanically the trim is working fine but the indicator is not responding)

Don Maxwell advised me on how to inspect the issue and thinks that one or more Clevis pins may have broken.

Does anyone know what the part numbers for these pins might be? 

Has anyone had a similar issue and if so what did you find? 
 

Thanks in advance for any help.

Michael

Edited July 26, 2022 by MrRodgers
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[KSMooniac]

Sounds like you'll have to open up the belly and see what has failed. The trim tube will be immediately obvious, as will be the U-joints that connect it to the wheel mechanism and the actuator in the back. Look for broken pins or tiny cotter keys in the belly panels as you remove them.

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[Shadrach]

What Don is suggesting is that there is a disconnect in the collection of trim tubes and u-joints that normally turn the jackscrew that actuates the tail.  As Scott says above look for broken or bent pins. The fastest way to locate the issue would be to open battery panel and observer the system while a helper turns the trim wheel in the cockpit. 

 

[Ragsf15e]

Simple explanation would be the chain link that connects your wheel to the trim tube is disconnected, broken link, etc.  belly panel right below the wheel needs opening.  Part 11 on the diagram.

[MrRodgers]

On 7/23/2022 at 10:04 PM, KSMooniac said:

Sounds like you'll have to open up the belly and see what has failed. The trim tube will be immediately obvious, as will be the U-joints that connect it to the wheel mechanism and the actuator in the back. Look for broken pins or tiny cotter keys in the belly panels as you remove them.

Sent from my LM-V405 using Tapatalk
 

Opened up the belly and found the issue was a broken bolt holding the wire to the trim indicator.  Mechanically the system works fine but the indicator was not working.

All fixed now.  Thanks for the input, everyone.

[MrRodgers]

On 7/24/2022 at 7:48 AM, Ragsf15e said:

Simple explanation would be the chain link that connects your wheel to the trim tube is disconnected, broken link, etc.  belly panel right below the wheel needs opening.  Part 11 on the diagram.

Opened up the belly and found the issue was a broken bolt holding the wire to the trim indicator.  Mechanically the system works fine but the indicator was not working.

All fixed now.  Thanks for the input, everyone.

[Ragsf15e]

35 minutes ago, MrRodgers said:

Opened up the belly and found the issue was a broken bolt holding the wire to the trim indicator.  Mechanically the system works fine but the indicator was not working.

All fixed now.  Thanks for the input, everyone.

Well that’s much better than the actual trim not working!

[Shadrach]

1 hour ago, MrRodgers said:

Opened up the belly and found the issue was a broken bolt holding the wire to the trim indicator.  Mechanically the system works fine but the indicator was not working.

All fixed now.  Thanks for the input, everyone.

Glad it’s working. A bit confused about the remedy. I thought that the tail was not moving when moving the trim wheel.  Was this just an indicator problem all along?

[BobbyH]

1 hour ago, Shadrach said:

I thought that the tail was not moving when moving the trim wheel.  Was this just an indicator problem all along?

Ross, you are not alone on this, it was stated that the tail section wasn't moving, yet I am happy it was a simple fix for him and the worst part was a misunderstanding.

Bob

[PT20J]

Since the tail puts quite a bit of force on the jackscrew creating friction, I'll bet there is a considerable difference in the torque felt at the trim wheel when the shaft is disconnected.

[kortopates]

Wow! glad it broke on the ground and not in the air.


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[Guest]

9 hours ago, MrRodgers said:

Opened up the belly and found the issue was a broken bolt holding the wire to the trim indicator.  Mechanically the system works fine but the indicator was not working.

All fixed now.  Thanks for the input, everyone.

Hopefully you had a travel board to set the stabilator and trim indicator in the correct position.

Clarence

[MrRodgers]

22 hours ago, Shadrach said:

Glad it’s working. A bit confused about the remedy. I thought that the tail was not moving when moving the trim wheel.  Was this just an indicator problem all along?

Yes, it turned out to be just an indicator problem.  

[MrRodgers]

14 hours ago, kortopates said:

Wow! glad it broke on the ground and not in the air.


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Me too.  Apparently, it happened after my landing when meeting friends for lunch at CMA. All good now.

Hope you are well.

[MrRodgers]

20 hours ago, BobbyH said:

Ross, you are not alone on this, it was stated that the tail section wasn't moving, yet I am happy it was a simple fix for him and the worst part was a misunderstanding.

Bob

Sorry for the confusion. 

[PT20J]

14 hours ago, M20Doc said:

Hopefully you had a travel board to set the stabilator and trim indicator in the correct position.

Clarence

Stabilator? Must be a Piper driver 

Actually it's pretty easy -- just align the elevator in trail with the stabilizer and set the indicator for the takeoff position. I know that works for a J because I used that as a before/after check that nothing got messed up when the GFC 500 with trim servo was installed.

Skip

[jamesm]

Glad it was an indicator problem and not a flight control problem. my stab trim indicator cable had broke several years back the cable had separated  from  indicator. I was able to get guy to weld/braze/solder it back together and check the travel against the travel board all is good.