In my capacity as a volunteer firefighter, I was called to a plane crash at our local airport. It was my buddy, in a C150M which I knew very well, who had affected a very unsuitable arrival angle relative to earth. I figured from the marks in the ground, that he stopped in about eight inches.
The inverted aircraft was remarkably intact in the cabin area - a strong testamonial to excellent Cessna design. We had no real trouble getting him out, as he was not trapped in at all.
The coroner, who knows such things, told me that based upon the examination, my buddy had experienced a 200G deceleration, which was not survivable for any duration.
But the airframe was not hugely collapsed, there was no head strike, and no entrapment. The propeller flange was a third peeled off the crankshaft though...
It is my opinion that the Cessna 150M displayed excellent crashworthiness. Even the seatbelt ripping would have provided its own amount of deceleration.
I do worry that the aircraft which use very rigid composite cabin structures, would have to be much more inventive to provide safe deceleration for the occupants inside the cabin, and is there room?
Seatbelt airbags? I've ridden in Cessna's test seat, and had the airbag blown at me. I suppose it's okay, but I am not keen on the requirement for a formal maintenance activity (and expense), when a seat is removed and reinstalled in the aircraft, and the bi-annual recertification, which is quite costly.
I put my trust in a well adjusted four point Hooker Harness!
Cheers, Pilot DAR