the helicopter isn't hanging upside down. its hanging facing downwards which is why they smashed through the windscreen and not the roof when they jumped. also when they crashed the c-123 and the wing clipped the tower the plane span in the direction of the clipped wing when logically it should spin away from the impact.
I saw this too, and thought the same at first. The chain does hang the right way though, toward the front of the helicopter, which points towards the ground. It is the camera which has been rotated so that the chain looks to be hanging forward.