It's not so much that it fell off the radar, it's that all those close to that sector of the industry are generally convinced there's nothing wrong with the 76 and things pointed to pilot error, months ago. Since only 3 people died, and everybody got lucky they didn't park it in some yuppie suburb like The Woodlands, it's not in the NTSB highest level of priority to throw everything at it, like they did Colgan 3407.
According to the RUMINT on APC and some of the folks from work who work for cargo outfits, FO apparently pooched it. Completely overreacted to an accidental TOGA actuation (or other reason for throttles going to max) and neither CA nor FO ever brought engines back through the sequence. The CVR and FDR apparently support the notion the FO pushed the column and thus airplane into 49 degrees NL, CA fought all he could, including apparently shearing the column retaining pin/bolt while pulling his column back while the FO pushed in a panic, like those people who whiskey throttle into a convenience store. CVR indicates tons of stuff hitting the ceiling, some rumor mill posits the sounds are congruent with even the jumpseater hitting the ceiling. According to APC, pictures of the stab trim ballscrew congruent with a trim position of 230 KIAS, aka, no runaway trim and certainly a position to be expected at the TOD before the whole thing went for a wild ride.
Basically, Occam's Razor again: Mishap crew lawndarted a perfectly functioning 767 into the muddy Houston swampline. Feel free to wait for the NTSB of course. Due diligence and all that. /sarc
Those who fly the 76 are really the ones to have most invested into it. If I flew one, I'd feel comfortable flying it all these months post-accident, based on what has been made available so far, on the mechanical side of the question. To each their own.