9:03 a.m. September 11, 2001: Primary Power Is Lost in WTC 7 When the South Tower Is Hit

Primary power is lost and internal alarms warn that there is no water pressure in World Trade Center Building 7 after Flight 175 crashes into the South Tower. [Bylicki, 6/19/2003; Jenkins and Edwards-Winslow, 9/2003, pp. 16 ] WTC 7 is a 47-story office building located about 370 feet north of the North Tower. [National Institute of Standards and Technology, 8/21/2008; National Institute of Standards and Technology, 11/2008, pp. 2] Immediately after Flight 175 hits the South Tower (see 9:03 a.m. September 11, 2001), it loses “primary power,” according to Richard Bylicki, a police sergeant assigned to New York City’s Office of Emergency Management, which has offices in the building. [Bylicki, 6/19/2003] Utility company Con Edison will later specify that two “open/auto” feeders, which distribute power from a substation, go off at this time. [9/11 Commission, 2/26/2004 ] The feeders trip automatically “as a result of collateral damage” caused by the plane hitting the tower, a report by the National Institute of Standards and Technology (NIST) will state. [National Institute of Standards and Technology, 11/2008, pp. 643] However, the building still has electricity, since, according to Bylicki, the power supply “switched to auxiliary generators.” Also at this time, Bylicki will state, the “fire alarm enunciator panel lit up, indicating there was no water pressure for fire suppression in the building.” [Bylicki, 6/19/2003] WTC 7 was built over a Con Edison electrical substation, which now provides power to the entire WTC complex. [National Institute of Standards and Technology, 11/2008, pp. 633] Several Con Edison employees are currently present in this substation. These employees will see “[n]o fire or significant physical damage” there before the site is evacuated, at around 10:20 a.m., according to NIST. [National Institute of Standards and Technology, 11/2008, pp. 357, 640] The electrical power in WTC 7 went off at 8:46 a.m., when Flight 11 crashed into the North Tower, but it came back on after a few seconds (see 8:46 a.m. September 11, 2001). [National Institute of Standards and Technology, 9/2005, pp. 109]