Looking inside I'm surprised more of the fuselage formers didn't break when the firewall cracked? I see a lot of air when I look at the first photo above inside the fuselage.
So am I! Can’t really determine exactly what happened, or how the airplane impacted. It was slowing down by that time, so much so that all three wheels were on the ground. Other than mud on one blade of the prop and a bump on the cowling, I couldn’t find any other signs of contact.
The firewall was made of three plies and one of them had delaminated and cracked between the two lower bolt holes, allowing the engine to move. All of the joints between the fuselage and firewall were solid, so it was a bit of a chore to drill and saw out.
I also think the engine bolts had been tightened over the years and compressed the plies, so that didn’t help.
Most of the damage in the photo below was from the removal process.
I also found a shot prior to the firewall install, which shows a good view of the structure.
Good news is that now it’s better than new.
