It is a quiet predawn morning in the Seattle, WA area and the lone FAA air traffic controller who is controlling the airspace south of the city has been on duty for seven hours. The only traffic is a Navy helicopter transiting the area westbound en route to a nearby Navy facility and a northbound private civilian seaplane. The controller, having dozed off, is awakened by the ringing telephone and learns that the two aircraft collided in flight in the controller’s airspace. There are no survivors. Investigation reveals that the two collided while in level flight at the altitude assigned each by that controller.

Analyze the potential liability of the United States and the controller for the accident.