[stevehawk]

It's not the cabin floor. it's what the cabin floor is attached to. Most fuselages have all of their longitudinal strength in their stringers, which are usually run along the floor. If the Cirrus had ripped through the bottom of that plane and not the top then that jet would have torn apart.

[londons_explore]

Stringers in a plane seem akin to stringers in a car frame... Cars have moved away to unibody designs (where the shell of the car is also the structure) because it is stronger, lighter and cheaper. Unibody designs have been the norm for almost 100 years now.

[hyperbovine]

Nit: SA-226 is a turboprop not a jet.