9:21 a.m. September 11, 2001: United Airlines Begins ‘Lockout’ of Flight 175 Information

Just before 9:22, United Airlines headquarters, located outside Chicago, begins the “lockout” procedure to restrict access to passenger and crew information about Flight 175. [9/11 Commission, 8/26/2004, pp. 26] This procedure is standard for airlines in safety and security incidents. As the 9/11 Commission will later describe, “It acknowledges an emergency on the flight and isolates information so that the case can be managed by top leadership at the airlines in a way that protects information from being altered or released, and also protects the identities of the passengers and crew.” [9/11 Commission, 8/26/2004, pp. 12-13] This procedure begins almost 40 minutes after Flight 175 was hijacked (see (Between 8:42 a.m. and 8:46 a.m.) September 11, 2001), and about 35 minutes after the plane’s transponder signal changed (see 8:46 a.m.-8:47 a.m. September 11, 2001). [9/11 Commission, 7/24/2004, pp. 7]