Having flown both types extensively (the Citabria and Super Decathlon) I would say they are both very safe airframes. Unless he got caught in a mountain wave, it's interesting that there was not even a quick broadcast on Unicom saying something was amiss. No ELT is also interesting. Unless it's sitting at the bottom of a lake or the Decathlon did not have one I wonder why it did not go off.

The Super D is stressed for +6 and -5 G with a 50% unlimited load factor above that so I doubt any kind of turbulence would have caused it to come apart. It also does glide quite well dead stick so even if the engine quit, he could have glided for a while. Lastly, his personal pilot said he did not like aerobatics so that makes the whole scenario even more interesting.

Hopefully he is OK and just waiting to be picked up somewhere so let’s all hope...

Beave