Crack found in my Xenos's tail post channel.

[Rynoth]

One leg of the "C" channel looks like it's split at the bend.

Indeed, an it's very fortunate that the OP caught this during pre-flight before it got worse, and fortunate for us that he shared it with us. In thinking through the worse case of a crack like this progressing, the side skin would still hold on to the rudder hinge for awhile longer. But eventually, if the hinge became detached, stub-rudder and ground steering authority would be diminished/lost. There still would be some yaw authority in the air though the ruddervators. Possible "flapping in the wind" of a loose stub rudder causing additional damage.

This emphasizes the importance of a good pre-flight inspection.

[peter anson]

Am I the only person that doesn't see a crack in the posted photo?

Wow, I'm with Michael on this. When you mentioned a crack I was looking for a tiny little crack with the potential to grow bigger. I didn't expect the whole flange to be falling off the channel. On the Sonex that channel is folded from 0.032" material with a 1/16" radius. Does it look like the fold was OK?

Peter

[Spaceman]

Sonex just sent out a required service bulletin for this issue. That was quick!

[Sonex Foundation]

https://www.sonexaircraft.com/service-bulletins/#xenos

[Rynoth]

Good on Sonex for jumping on this. I inspected mine today and found that it was difficult/impossible to visually see the actual channel bend without pulling the hinge pin and removing the rudder due to the tail post doubler being in the way.