I would have thought that a very high value of longitudinal deceleration would have been against it. More damage to the fuselage would have been desirable.
Concur with those thoughts.
And of course the vintage of the seats and restraints (9G longitudinal).
I have no idea what standards applied to the original Beaver certification (and am not overly interested in searching them out) but, being of ancient vintage, it might even predate the 9G static restraint.
re the seats... they may be of a rated G but what are the floor tracks?
Depending on the seat certification, one would expect that the seats are matched to the more restrictive of the aeroplane certification requirements and the seating standards of the day. Certainly that was the process at Ansair (an Ansett subsidiary, now long defunct) when, for many years, I was the certification delegate for aircraft seat manufacture.
accident (turbine DC3) that stalled on takeoff in ground effect and slid across the snow to a halt. Everyone survived, still safely in their seats. Except they were neatly piled up in the front end of the fuselage...
Again, one would need to know the relevant standards for the particular aircraft. The original DC3s had 6g static seats.