Flap Connection Worn

[4012]

I recently discovered that the flaps on my Cessna 140 A were not deploying evenly in the air.
Upon inspection it appears the connection between the flap torque tube and the flap bracket is worn allowing excessive movement.
Can anyone suggest a repair procedure I might use to fix this problem, other that replacing the worn parts.
Thanks

[V529]

That's a pretty typical situation. I'm assuming the "slots" that the bolt goes through from the fuselage tube, to the flap tube is elongated? Other than replacing parts, It may be possible to weld the holes and then re-machine.

[6643]

Resist the temptation to replace the slots with holes. The distance between the two flaps changes slightly as you lower and raise the flaps. If you have bolts in holes one of the inner flap hinges will crack.

[4012]

Thanks for that tip. I have read about this topic somewhere but I cant seem to locate the site where I saw it last time.
As pointed out the oblong hole is critical to maintain and if so would seems to indicate that a replacement flap bracket would be the best way to go if you can find one. (Or weld the holes and refabricate the long hole)
The flap bracket part number for the 140A is 0410212.
Univair has a bracket for the 140 which is 0425118.
Does anyone know if these are interchangeable?
Thanks

[4012]

These part numbers are not correct.
The part number I was looking for is 0426907-1. That is a right Hand flap bracket for the 140 A
I have learned a lot about this issue since investigating it and I would be willing to share my information if anyone is interested.
The Flap brackets on the 140 are not the same.

[8434]

Hi 4012, I'd love to see some pictures of the Flap Bracket to Torque Tube attachment. I noticed one flap has been a bit lower than the other on my 140 and I plan to inspect it. I'm guessing the Torque tube hole has elongated but I wouldn't mind having some more information when I get into it.
Thanks

[4012]

Sorry, I don't read these posts much. I didn't see your response.
Did you repair your flap brackets?
I had to purchase two new brackets and have a torque tube manufactured. It wasn't difficult providing you got the right material for the tube.
I found that someone in the past had rewelded the holes in the flap brackets and then installed them and the torque tube upside down!
This changed the geometry of the mechanism so the flaps didn't work properly.
It was an interesting exercise. I also changed all the flap hinges.
I still have one unused new old flap bracket left over.
By the way, Cessna Engineering sent the correct drawings to me and I was able to determine what went wrong. They were most helpful.
Good luck
4012 (John)

[aviacs]

love to see some pictures of the Flap Bracket to Torque Tube attachment. I noticed one flap has been a bit lower than the other on my 140 and I plan to inspect it. I'm guessing the Torque tube hole has elongated but I wouldn't mind having some more information when I get into it

What was the resolution?

Here are the Univair brackets mentioned in another post:
https://www.univair.com/search.php?sear ... chy=Cessna

Is there an approved repair for the torque tube hole?
Is there a spec or "commonly accepted practice" for how much axial rotation between the parts is too much?

smt

[8434]

I ended up finding the flap bracket had an oval slot (wider - its designed to be a slot) as well as a crack on the upper attachment to the flap. I replaced the flap bracket and this fixed the droopy flap.

flap.jpg (148.04 KiB) Viewed 4929 times

I inspected the torque tube and found it to be in pretty good shape, I can see some early signs of wear in the bolt holes but once I put it back together the wasn't much play in in the flaps.

I'm left with one question, is the slot in the flap bracket there to allow for a change in geometry as the flaps are moved though their range of motion - the bracket would slide in and out of the torque tube in flight? OR is it there to make installation easier since the flaps on either side would have to line up exactly with the torque tube length and any variation in flap hinge position would make it impossible to install the bolt?

I had my mechanic actuate the flaps while I looked for movement of the bracket inside the tube. I didn't see any.

[aviacs]

8434-

Thank you much for the follow-up.

The subject airplane no doubt has some wear in the flap bracket slot.
However, almost all of the motion can be noticed/accounted for by wear & distortion ("wallering") in the torque tube cross hole, & "some" on the ends of the cross bushing.

That is also an interesting question regarding the longitudinal slots. (The slots can bee seen in the Univair brackets in my link above)
My guess, and it is only that, is that the parts are intended to accommodate sliding in use (not just at assembly) due to the configuration (survey sample of 2 only) of the steel bushings. They are just long enough that the cross bolt cannot actually clamp on or distort the torque tube. (cannot pinch it tight on the bracket stub or distort roundness.) In the subject airplane, the bolt/bushing assembly can be rotated or very slightly shifted lengthwise (to the bolt) when the bolt is tight. Again, one flap has lost motion/freeplay of "several" degrees between the TT & the bracket, the other has nil.

Can you confirm that each TT-bracket assembly has a steel bushing retained in the cross hole by the bolt?
Since it is not specifically shown in our paper parts catalog, there has been discussion as to whether the bushings are original. I don't think they could be anything but original, however confirmation from other sources would be appreciated. The bushing is aprox .360" dia.

Thanks!