A picture spells a thousand words and I've been sent a few (2 of which I'm posting) which show what happened to an AA MD-83 last weekend at DFW. She'd gone in for maint.. part of which was to check for corrosion.
As soon as weight went onto the rear jack position, it became evident just how corroded the old girl was.. in that area at least! Glad I don't have to fly on one!
I have my doubts about corrosion. I suspect it's more likely a badly/incorrectly placed jack or forgotten weight that overloaded the jack pad. We had a 727 at Denver do this when someone forgot to unload the aft lav and galley. Everything seemed fine for a little while, then all of a sudden (about 3 feet in the air) the jack pad failed and the plane came crashing down. As with any tail-engined aircraft, they are pretty tail heavy even when empty, so the jacks don't have to necessarily slide for the plane to sit on its tail. I saved a few 727 tail sits during my fueling days because someone forgot to secure the tail stand or tail stairs and catching the plane starting to tip before it went all the way back and either stuffing a bunch of fuel in the center tank to bring it back forward or getting back and securing the tail.
I still like the way that FedEx secures the planes. They not only use a tail stand to help keep the plane off its rear, they also strap the nose gear down. They've never had one go "tail low" when using that procedure.
Glad I don't have to fly on one! 
...would have sounded just like the sound a jack makes when it punches through the skin of an MD-83 
