United Airlines flight dispatcher Ed Ballinger sends a warning message to the flights he is monitoring, which include Flight 93. [9/11 Commission, 8/26/2004, pp. 39] Ballinger is responsible for monitoring 16 transcontinental flights. [Chicago Daily Herald, 4/14/2004] Beginning at 9:32, he sends out a text message to these flights: “High security alert. Secure cockpit.” He presumably sends this in response to United Airlines’ notification a minute earlier that there is a potential problem with Flight 93 (see 9:31 a.m.-9:32 a.m. September 11, 2001). Ballinger’s message is transmitted to Flight 93 at 9:33, but the plane does not respond. Ballinger apparently informs his colleagues of this lack of response: United Airlines Chief Operating Officer Andy Studdert will later tell the 9/11 Commission that at “approximately 9:30, a United dispatcher reports that we cannot reach Flight 93.” [9/11 Commission, 1/27/2004; 9/11 Commission, 8/26/2004, pp. 39] Ballinger previously sent out a message at 9:19, warning his flights to “Beware any cockpit intrusion” (see 9:19 a.m. September 11, 2001). [9/11 Commission, 7/24/2004, pp. 11]