This is a great paper, but I really wonder how much difference it made. The conclusion says

    The greatest probability of being destroyed is .534, and occurs
    when a plane is hit by a 20-mm cannon shell in the engine area.
    The next most vulnerable event is a hit by a 7.9-mm machine gun
    bullet on the cockpit.

I think most people would suggest that these are the parts worth protecting the most.

Another thing, I'm not sure that the method is unobvious. This is not the fault of the author but of the fairly breathless retellings that sound like an episode of 'Numb3rs'