Unless it was a training accident from some difficult maneuver, I guarantee it was worn out equipment failure..................
The chances of equipment failure is very low within The Thunderbirds, they have the best of the best in the entire group.
Not saying that it’s impossible but very low probability.
I hate to say it but most likely Pilot error.
IIRC one time one of the Pilots screwed up on setting the Altimeter for the Base of the day. He punched out just as the plane belly slammed the ground.
There have been engine failures but not often.
RIP Sir and Thank You for Your Service.