As we turn to the events of September 11, we are mindful of the unfair perspective afforded by hindsight. Nevertheless, we will try to describe what happened in the following 102 minutes:

• the 17 minutes from the crash of the hijacked American Airlines Flight 11 into 1 World Trade Center (the North Tower) at 8:46 until the South Tower was hit
• the 56 minutes from the crash of the hijacked United Airlines Flight 175 into 2 World Trade Center (the South Tower) at 9:03 until the collapse of the South Tower
• the 29 minutes from the collapse of the South Tower at 9:59 until the collapse of the North Tower at 10:28

From 8:46 until 9:03 A.M.
At 8:46:40, the hijacked American Airlines Flight 11 flew into the upper portion of the North Tower, cutting through floors 93 to 99. Evidence suggests that all three of the building's stairwells became impassable from the 92nd floor up. Hundreds of civilians were killed instantly by the impact. Hundreds more remained alive but trapped.³⁰

Civilians, Fire Safety Personnel, and 911 Calls North Tower

 A jet fuel fireball erupted upon impact and shot down at least one bank of elevators. The fireball exploded onto numerous lower floors, including the 77th and 22nd; the West Street lobby level; and the B4 level, four stories below ground. The burning jet fuel immediately created thick, black smoke that enveloped the upper floors and roof of the North Tower. The roof of the South Tower was also engulfed in smoke because of prevailing light winds from the northwest.³¹

Within minutes, New York City's 911 system was flooded with eyewitness accounts of the event. Most callers correctly identified the target of the attack. Some identified the plane as a commercial airliner.³²

The first response came from private firms and individuals-the people and companies in the building. Everything that would happen to them during the next few minutes would turn on their circumstances and their preparedness, assisted by building personnel on-site.

Hundreds of civilians trapped on or above the 92nd floor gathered in large and small groups, primarily between the 103rd and 106th floors. A large group was reported on the 92nd floor, technically below the impact but unable to descend. Civilians were also trapped in elevators. Other civilians below the impact zone-mostly on floors in the 70s and 80s, but also on at least the 47th and 22nd floors-were either trapped or waiting for assistance.³³

It is unclear when the first full building evacuation order was attempted over the public-address system. The deputy fire safety director in the lobby, while immediately aware that a major incident had occurred, did not know for approximately ten minutes that a commercial jet had directly hit the building. Following protocol, he initially gave announcements to those floors that had generated computerized alarms, advising those tenants to descend to points of safety-at least two floors below the smoke or fire-and to wait there for further instructions. The deputy fire safety director has told us that he began instructing a full evacuation within about ten minutes of the explosion. But the first FDNY chiefs to arrive in the lobby were advised by the Port Authority fire safety director-who had reported to the lobby although he was no longer the designated fire safety director-that the full building evacuation announcement had been made within one minute of the building being hit.³⁴

Because of damage to building systems caused by the impact of the plane, public-address announcements were not heard in many locations. For the same reason, many civilians may have been unable to use the emergency intercom phones, as they had been advised to do in fire drills. Many called 911.³⁵

The 911 system was not equipped to handle the enormous volume of calls it received. Some callers were unable to connect with 911 operators, receiving an "all circuits busy" message. Standard operating procedure was for calls relating to fire emergencies to be transferred from 911 operators to FDNY dispatch operators in the appropriate borough (in this case, Manhattan).Transfers were often plagued by delays and were in some cases unsuccessful. Many calls were also prematurely disconnected.³⁶

The 911 operators and FDNY dispatchers had no information about either the location or the magnitude of the impact zone and were therefore unable to provide information as fundamental as whether callers were above or below the fire. Because the operators were not informed of NYPD Aviation's determination of the impossibility of rooftop rescues from the Twin Towers on that day, they could not knowledgeably answer when callers asked whether to go up or down. In most instances, therefore, the operators and the FDNY dispatchers relied on standard operating procedures for high-rise fires-that civilians should stay low, remain where they are, and wait for emergency personnel to reach them. This advice was given to callers from the North Tower for locations both above and below the impact zone. Fire chiefs told us that the evacuation of tens of thousands of people from skyscrapers can create many new problems, especially for individuals who are disabled or in poor health. Many of the injuries after the 1993 bombing occurred during the evacuation.³⁷

Although the guidance to stay in place may seem understandable in cases of conventional high-rise fires, FDNY chiefs in the North Tower lobby determined at once that all building occupants should attempt to evacuate immediately. By 8:57, FDNY chiefs had instructed the PAPD and building personnel to evacuate the South Tower as well, because of the magnitude of the damage caused by the first plane's impact.³⁸

These critical decisions were not conveyed to 911 operators or to FDNY dispatchers. Departing from protocol, a number of operators told callers that they could break windows, and several operators advised callers to evacuate if they could.³⁹ Civilians who called the Port Authority police desk located at 5 WTC were advised to leave if they could.⁴⁰

Most civilians who were not obstructed from proceeding began evacuating without waiting for instructions over the intercom system. Some remained to wait for help, as advised by 911 operators. Others simply continued to work or delayed to collect personal items, but in many cases were urged to leave by others. Some Port Authority civilian employees remained on various upper floors to help civilians who were trapped and to assist in the evacuation.⁴¹

While evacuating, some civilians had trouble reaching the exits because of damage caused by the impact. Some were confused by deviations in the increasingly crowded stairwells, and impeded by doors that appeared to be locked but actually were jammed by debris or shifting that resulted from the impact of the plane. Despite these obstacles, the evacuation was relatively calm and orderly.⁴²

Within ten minutes of impact, smoke was beginning to rise to the upper floors in debilitating volumes and isolated fires were reported, although there were some pockets of refuge. Faced with insufferable heat, smoke, and fire, and with no prospect for relief, some jumped or fell from the building.⁴³