at the Duluth Sector Direction Center saw a figure climbing the security fence. He shot at it and activated the sabotage alarm, which automatically set off similar alarms at other bases in the region. At Volk Field in Wisconsin, a faulty alarm system caused the Klaxon to sound instead, which ordered Air Defense Command (ADC) nuclear-armed F-106A interceptors into the air. The pilots had been told there would be no practice alert drills and, according to political scientist Scott D. Sagan, "fully believed that a nuclear war was starting". Before the planes were able to take off, the base commander contacted Duluth and learned of the error. An officer in the command center drove his car onto the runway, flashing his lights and signaling to the aircraft to stop. The intruder was discovered to be a bear. Sagan writes that the incident raised the dangerous possibility of an ADC interceptor accidentally shooting down a Strategic Air Command (SAC) bomber. Interceptor crews had not been given full information by SAC of plans to move bombers to dispersal bases (such as Volk Field) or the classified routes flown by bombers on continuous alert as part of Operation Chrome Dome. Declassified ADC documents later revealed that "the incident led to changes in the alert Klaxon system [...] to prevent a recurrence". 27 October 1962 At the height of the Cuban Missile Crisis, Soviet patrol submarine almost launched a nuclear-armed torpedo while under harassment by American naval forces. One of several vessels surrounded by American destroyers near Cuba, B-59 dove to avoid detection and was unable to communicate with Moscow for a number of days. began dropping practice depth charges to signal B-59 to surface; however the captain of the Soviet submarine and its zampolit took these to be real depth charges. With low batteries affecting the submarine's life support systems and unable to make contact with Moscow, the commander of B-59 feared that war had already begun and ordered the use of a 10-kiloton nuclear torpedo against the American fleet. The zampolit agreed, but the chief of staff of the flotilla (second in command of the flotilla) Vasily Arkhipov refused permission to launch. He convinced the captain to calm down, surface, and make contact with Moscow for new orders. On the same day, an American U-2 spy plane was shot down over Cuba, and another U-2 flown by United States Air Force Captain