Flaperon Control Break

[vastine pilot 2]

I was just curious if anyone has seen this... this is the first I've seen. It's usually a flaperon bracket that broke.

https://www.caa.govt.nz/assets/legacy/Airworthiness_Directives/Continuing_Airworthiness_Notices/CAN-27-012.pdf

 

[BryceKat 125]

No, I haven’t seen this. Thanks for posting, it’s definitely going to be on my preflight! Ps: I like the shirt in your avitar!

[flywise 169]

I am very surprised that you would loose control when only one flaperon is connected to your stick instead of two. In my manual Avid states that you can control roll (if flaperons are completely u/s or disconnected) with rudder only. In the above scenario he still had one flaperon working + rudder!!!

Any thoughts?

[smilemikey 3]

Not knowing the whole story, I can see how the loss of or added drag for the flaperon letting go could cause a loose of control.  I had an RC do something like that to me once. 

[flywise 169]

The flaperon being fitted with counterweights/balanced should just sit in a neutral position in the airflow....at least that's what I thought.

Anyone to shed some light?

[nlappos 413]

I think the loss of one aileron would reduce the control power in half, and on short final, the change would catch many of us by surprise. This could very well lead to the case where the roll control was very sloppy, and ground contact becomes more likely.

I think the evidence that the right flaperon control rod sheared, and the flaperon went neutral (right on flywise) would be fairly benign if it happened in cruise and you had some time to work it out.

I doubt that the flaperon breaking at the control rod would make more drag on the broken side, but it would make an unbalanced drag, where the broken right flaperon would have low drag and the unbroken left one would have high drag, with the flap setting. You would think this could make the aircraft yaw left and roll left(strong dihedral effect), but the fact that the left had lots of flap setting would look like lots of right aileron, so the aircraft would roll right sharply. 

It stands to reason that the rod would shear with large flap input, since the twisting of the rod is how we fight the normal flap force to streamline, so the torsion on that rod would be a maximum with high flap settings.

Edited 19 Nov 2018 by nlappos

[Cloud Dancer 69]

I think the broken side would have a tendency to develop flutter which could easily result in partial loss of control.