Shortly After 9:44 a.m. September 11, 2001: Change of Course and Pilot’s Failure to Respond to Message Lead Cleveland Center to Again Suspect Delta 1989 Is Hijacked

Having earlier concluded that it was not hijacked, air traffic controllers at the FAA’s Cleveland Center again become suspicious of Delta Air Lines Flight 1989, after its pilot requests a change of course and then fails to respond to a message.
Pilot Requests Diversion – Cleveland Center controllers initially thought the sounds from Flight 93 as it was being hijacked had come from Delta 1989, but soon decided they had come from Flight 93 (see (9:28 a.m.-9:33 a.m.) September 11, 2001). [USA Today, 8/13/2002] However, without notifying the Cleveland Center, Delta Air Lines has just instructed Delta 1989 to land at Cleveland Hopkins Airport (see (9:42 a.m.) September 11, 2001). After the plane’s pilot, Captain Paul Werner, calls the Cleveland Center at 9:44 a.m., requesting an immediate diversion, controllers there become suspicious. [Spencer, 2008, pp. 167-168; USA Today, 9/11/2008]
Supervisor Reports Concerns over Teleconference – USA Today will later describe: “The Delta flight wants to land in Cleveland? And the captain’s request comes before he can know that the FAA wants every flight down. On this day, the fact that the pilot requests to be rerouted before he is ordered to land seems suspicious. Why the urgency? Controllers don’t know that Delta officials, also concerned about the flight, have ordered Werner to land in Cleveland.” After Delta 1989 makes an abrupt 30-degree turn back toward Cleveland Airport, a supervisor at the Cleveland Center announces the apparently suspicious development on an FAA teleconference.
Coded Message Confirms No Hijacking – As Delta 1989 begins its descent toward Cleveland, a Cleveland Center controller radios Werner with a coded message to check whether his plane has been hijacked. The controller says, “Delta 1989, I hear you’re ‘late’ today.” (The controller is using the code word for a hijack, which has been replaced with the word ‘late’ in subsequent accounts of this incident, for security reasons. Pilots can use this code word to alert controllers to their situation if they are unable to do so openly because hijackers are in the cockpit.) Werner reassures the controller that all is okay, saying: “Negative. Delta 1989 is not a ‘late.’”
Lack of Response Causes More Suspicion – Then, as the plane descends, it receives another message from the Cleveland Center. But Werner, who is busy, fails to respond to it. This arouses further suspicion. According to USA Today: “On the ground, controllers in Cleveland Center grow alarmed. Why didn’t he respond? Have both jets—the United [Flight 93] and the Delta flights—been hijacked?” [USA Today, 8/13/2002; Spencer, 2008, pp. 168-169]