The crash on approach with very few thousands of horizontal linear feet to go, is just plain strange. In any of the crashes you can not blame the airframe, and the years and the flights on them prove they are a very solid well designed plat form. Of course one thing that could have caused a last minute approach crash is a medical issue with the pilot. Radial engines? Can only blame all the people involved with overhauling and maintaining them, well yes operators as well. Just don't have the same quality of people working on them now as back in the old days, and not saying all them were perfect either.
Then there is what seems to be a hidden push to get rid of the old high powered piston powered aircraft, reminiscent to the old waning days of steam trains (when they were cut up and scrapped en mass, with only a handful left), that started with the grounding of the old firebombers years ago. And it wasn't even an old piston plane that pushed that decision, it was the wings coming off the 130 turbo prop Hawkins and Powers plane. What is driving that push is difficult to figure out, some would think its the leaded fuel issue, it seems its more than that though.
Strange airplane crashes etc. read a book called "The Great Lakes Triangle" By Jay Gourley, he actually writes about planes with pilots that are with high hour experience going down for no reason. Its just sad and weird that 2 of these type planes were lost with in such a short time period, both under strange circumstances. And just like the B17 an engine out should not affect the design ability of the plane to maintain altitude, a non feathered prop is the only thing that will cause enough drag to do that.