At 9:51 a.m., a helicopter pilot cautioned that "large pieces" of the South Tower appeared to be about to fall, and posed a danger to those below. Immediately after the collapse, another helicopter pilot radioed the news. The FDNY chiefs would have benefited greatly if they had been able to communicate with the helicopter pilot. 57 minutes after the second attack, at 9.59 a.m. the South Tower collapsed. It took only 30 seconds for the tower to collapse entirely. 600 people died in this tower, 500 of them were those trapped above the point of impact.