A drilling rig recently experienced a major incident when the gooseneck and kelly hose became completely detached from the top drive. The kelly hose was chained to the frame of the top drive, but the chain parted when the gooseneck separated form the top drive with 5000 psi pump pressure. This caused the entire gooseneck assembly and kelly hose to fall to the rig floor. Before the driller could shut down the pumps, the entire rig floor area was sprayed with oil-based mud. Fortunately, there were no injuries.