I know the guy in the back seat who lived. His 6 year old is in mine's 1st grade class, he also has a 3 and a 1 and a half year old. Scary stuff.
He told his wife that they never touched the ground. They were right above the runway and the plane flipped over and hit the ground upside down.
He never lost conciousness, kicked out the window and crawled out. He was walking around when ARFF got there. They operated last night, he has internal organ lacerations from the seat belts.
He is expected to fully recover.
He is not a pilot, but his description sounds like an encounter with vortices, as mentioned above.
Let's watch those heavies gang....