As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
REAR SEAT PN 7-1500 FAILED AT THE LT HINGE POINT. THE AN3 SERIES BOLT PULLED THRU THE HINGE LUGS WHICH ARE WELDED TO THE SEAT FRAME BOTTOM. THE RT HINGE HOLES SHOW ELONGATION, BUT REMAINED INTACT. THE AC WAS DOING SPIN TRAINING AT THE TIME OF THE INCIDENT. RECOMMEND THAT THE SEAT FRAME BE MODIFIED TO CURRENT STANDARDS INSTALLED ON NEWER AC. (K)