[Gunrunner2]

Absolutely.

The question remains: The jet was established in a stable turn, and after what I figure was about 270 degrees of turn, it rolled over. . .what would cause this?

(For those that don't fly, the stick is centered right after you establish your desired bank angle. This is not like a car where you turn the wheel and hold it there during the turn. In an aircraft, you center the stick once you achieve the desired bank angle as this neutralizes the ailerons and stops the banking maneuver.)

Given the Russians loss of face, I wonder if we will ever find out the "cause" of the mishap?

[Light Speed]

I imagine some intel branches with advanced digital scan could see the configuration on the wings and flaps...millisecond world..but probably where the problem lies.
The SU-27 is said to have a very good thrust ratio..one engine is sufficient to power out if the second fails.
I saw some lateral slide prior to this 27's crash.
If the pilot tried to thrust out..the nose would have pitched upward..and we would have seen it.
The plane simply dropped!
will probably have to wait for Flight Journals or Janes intel commentary...sometimes "Combat Aircraft" mag carries intel evaluation on flight accidents.
Anyway...How do you say " Computer Glitch" in Ukranian?

[El Gato]

Given the Russians loss of face

That would be the Ukranians. This incident follows the one in which they shot down that airliner during an exercise.