Shortly after air traffic controllers ask Flight 11 to climb to 35,000 feet, its transponder stops transmitting. A transponder is an electronic device that identifies a plane on a controller’s screen and gives its exact location and altitude. Among other vital functions, it is also used to transmit a four-digit emergency hijack code. Flight control manager Glenn Michael later says, “We considered it at that time to be a possible hijacking.” [Christian Science Monitor, 9/13/2001; MSNBC, 9/15/2001; Associated Press, 8/12/2002] Initial stories after 9/11 suggest the transponder is turned off around 8:13 a.m., but Pete Zalewski, the air traffic controller handling the flight, later says the transponder is turned off at 8:20 a.m. [MSNBC, 9/11/2002] The 9/11 Commission places it at 8:21 a.m. [9/11 Commission, 6/17/2004 
] Colonel Robert Marr, head of NEADS, claims the transponder is turned off some time after 8:30 a.m. where the Flight 11 hijack was first detected a.m. [ABC News, 9/11/2002]
8:21 a.m. September 11, 2001: Boston Controller Suspects Something Seriously Wrong with Flight 11, but NORAD Not Notified
Boston flight controller Pete Zalewski, handling Flight 11, sees that the flight is off course and that the plane has turned off both transponder and radio. Zalewski later claims he turns to his supervisor and says, “Would you please come over here? I think something is seriously wrong with this plane. I don’t know what. It’s either mechanical, electrical, I think, but I’m not sure.” When asked if he suspected a hijacking at this point, he replies, “Absolutely not. No way.” According to the 9/11 Commission, “the supervisor instructed the controller [presumably Zalewski] to follow standard operating procedures for handling a ‘no radio’ aircraft once the controller told the supervisor the transponder had been turned off.” Another flight controller, Tom Roberts, has another nearby American Airlines Flight try to contact Flight 11. There is still no response. The flight is now “drastically off course” but NORAD is still not notified. [MSNBC, 9/11/2002; 9/11 Commission, 6/17/2004 ] Note that this response contradicts flight control manager Glenn Michael’s assertion that Flight 11 was considered a possible hijacking as soon as the transponder was discovered turned off.
