You got it 
In my years in the USAF, I did some instrument instructing in the "J" model while in the reserves, mostly safety pilot time, but in talking with some of the old guys, Air Force tired of trying to teach non-pilot flight engineers or Navigators how to make an emergency landing on 1 engine. I think they lost 3 or 4 at Kessler AFB in Mississippi trying to train emergency "pilots" in case the aircraft commander was KIA or injured beyond help in landing the "bird" Don't know how accurate those stories were, as time sometimes "embellishes" the true facts. I think "wiser" heads pevailed and they added the co-pilot as being as neccessary as the nose wheel.