CTSW,CTLS Stabilator moving front to back

[Tad Olmsted]

During a 100 hr inspection of a CTLS I found the horizontal stabilator to be loose and moved front to aft. I grabbed the outboard edge of the horz stab to check for security and found excessive play. I checked the torque and it was right on the money, so I started my investigation.

 

The problem wasnt the stab itself, but rather the steel bracket that holds it on. The 2 bolts fit very snuggly in the stab as designed, but with the stab on the bench I checked the steel bracket with the bolts and came to the conclusion.

 

I happened to have 2 other CT's in my shop. One was a SW and the other was a LS. The SW was fine, but the LS had the same play as well. This meant 2 out of the 3 CT's in my shop for MX had excessive play in the horz stab.

 

As luck would have it, Daniel from Germany was in Sebring and we came up with a mod for the steel pivot bracket that holds the horz stab on the A/C. There is only one other CT that has had this problem ( 3 total worldwide), but I want all CT owners and MX stations to be aware and recommend checking this area. I have the LOA for the mod and can forward any info to anyone who might need it.

[Tad Olmsted]

Here is the drawing from FD

FD stab drawing.pdf

[Runtoeat]

Tad, I looked at the mod drawing and tried to understand just what is loosening up by re-reading your post. Is the problem caused by the bolt holes in the steel stab braket opening up and allowing the bolts to move around? Is the washer shown on the drawing added to re-establish a new hole of correct size for the bolt?

[Tad Olmsted]

You are correct on both. I can turn down the new bushings on the lathe and send them to anyone who needs them.

 

you need to open the holes up to 10 mm and get longer bolts. If you have trouble finding the hardware or bushings locally, I can put a kit together

[Jacques]

here is a picture (seen from top) of my stab bracket

 

the 2 lower holes seems elongated a bit

 

Tad,, that steel bushing that you place there..how does it stay there ?

 

thanks

[Tad Olmsted]

In the drawing you will see 4 small tack welds that hold the new bushings in place. The bushings are clamped by the 2 horz stab bolts and are not going anywhere. However the purpose for the welds are in case the stab is removed, the bushings will stay in place.

 

If your bolt holes are elongated you will most defineately need this mod. I garentee if you reinstall the stab, it will move front to aft. The last thing we want is horz stab flutter. I know first hand, and it is something you never want to experience.

 

I have been getting a lot of calls and emails on this one. During your pre-flight walk around it is a good idea to check this area.