I don't know about the ATR, but the rest of the aircraft can carry their own engines.
By outsize cargo, I don't mean palletized cargo that's large. I am talking about things like oil drilling equipment, large vehicles, large helicopters. Those will not fit in the side door of a SF
. I have flown SFs and have watched the loadmasters try to load things that should have fit through the side door. Believe me, it's not a pretty sight!
My point was FedEx has a different requirement for their "freighter". If you look at CX
the majority of their freighters are pure freighters (in the case of SQ
100%). From a marketing point of view you have many more markets available. One of my last trips through SHJ
we had large military vehicles onboard. They would only fit through the nose door.