I'd be very very surprised if anyone can find me a CH-47 of any model or mark that can make it 55km with an internal or external load (even including the crew and butty boxes) weighing 20,000kgs! Unless the carbon-fibre programme has made the airframe weigh a 3rd of the original weight!
(before anyone says it, an AUM of 20,000kgs would get quite a lot further... likewise a load of 20,000lbs)