In theory, can jetliners remain controllable after losing the entire tail section? The scenario here is a detachment of the tail,one with the whole empennage.
Could a variant of an existing model of swept winged jet airliner be made to remain controllable, using ailerons, differential flaps, differential spoilers and differential thrust, used for pitch, roll and yaw, regulated by an appropriate autopilot program, and with no other modifications?
No - though the vertical stabilizer might be worked around, the same is not true for the horizonal stablizer. Without it you will loose stability in the pitch axis so much that I doubt there will be any chance for a controlled flight on nearly all aircaft (though there is a possibility that a few ones might remain some kind of controllability)