sentences:  If the communication link between North American Aerospace Defense Command and the base was severed, the aircraft crew could determine if the interruption resulted from an attack or a technical failure.The monitoring mission started when the designated aircraft reached a waypoint at in Baffin Bay and entered a figure-eight holding pattern above the air base at an altitude of .In 1966, United States Secretary of Defense Robert McNamara proposed cutting "Chrome Dome" flights because the BMEWS system was fully operational, the bombers had been made redundant by missiles, and $123 million ($ as of ) could be saved.