Yes, its one of the pre-production prototypes, hopefully not 055, as she is one of my favorites, with a civilian test pilot according to Fox News, Russia....
As noted the first production aircraft is scheduled to deliver today, this will put a damper on the ceremonies, in fact the factory bird was likely going to be doing a formation fly by with the first production aircraft would be my best guess? but that's just me putting the pieces together??? so we shall see what the circumstances were, but I wouldn't be a bit surprised if that bird was to be part of today's festivities.....
No, it was indeed the first serial production aircraft - alond since no other aircraft was there at that unlucky moment - during a factiry test flight prior to delivery.
Russian sources say there was an issue with the FCS.
At least the pilot survived.