Just checked the Jepps for runway 24 at EDNY and the glide-slope intercept is indeed 8.9nm/16km at 4000'. So they went down just as the AP would be trimming forward. The METARs also show optimal icing conditions. So if the tailplane was loaded with ice, this might well have caused tailplane stall. Possibly exacerbated if they had also selected flaps at "half point above the glide" as taught by some ATOs.