Vraciu - following Occam's razor approach, it would be easiest to surmise that they lost an engine and following Busher's point if you can't feather the engine because of a failure, you're now in a negative climb rate.
Then it's just a math exercise. What's going against them?
1. The B-17 engines are as aerodynamic as a shoebox.
2. The B-17 airplane itself an aerodynamic model from the late 1930s
3. The aircraft was at 500' and Altitude = Energy
4. Based on Busher's comment on the C-130, the B-17 had just 500' of energy to turn around, and re-line-up for final.
Unfortunately, the math didn't add up to a successful probable landing.
![Sad :(](http://bbs.hitechcreations.com/smf/Smileys/default/frown1.gif)
It does beg the question... these old birds... is it worth it to keep them flying like this knowing how vulnerable they are when things go wrong? Old design = little room for issues?