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it had been hijacked. At 9:25, the Command Center advised FAA headquar-
ters of the situation.
The failure to find a primary radar return for American 77 led us to inves-
tigate this issue further. Radar reconstructions performed after 9/11 reveal that
FAA radar equipment tracked the flight from the moment its transponder was
turned off at 8:56. But for 8 minutes and 13 seconds, between 8:56 and 9:05,
this primary radar information on American 77 was not displayed to controllers
at Indianapolis Center.
The reasons are technical, arising from the way the
software processed radar information, as well as from poor primary radar cov-
erage where American 77 was flying.
According to the radar reconstruction,American 77 reemerged as a primary
target on Indianapolis Center radar scopes at 9:05, east of its last known posi-
tion.The target remained in Indianapolis Center's airspace for another six min-
utes, then crossed into the western portion of Washington Center's airspace at
9:10.As Indianapolis Center continued searching for the aircraft, two managers
and the controller responsible for American 77 looked to the west and south-
west along the flight's projected path, not east--where the aircraft was now
heading. Managers did not instruct other controllers at Indianapolis Center to
turn on their primary radar coverage to join in the search for American 77.
In sum, Indianapolis Center never saw Flight 77 turn around. By the time
it reappeared in primary radar coverage, controllers had either stopped look-
ing for the aircraft because they thought it had crashed or were looking toward
the west. Although the Command Center learned Flight 77 was missing, nei-
ther it nor FAA headquarters issued an all points bulletin to surrounding cen-
ters to search for primary radar targets. American 77 traveled undetected for
36 minutes on a course heading due east for Washington, D.C.
By 9:25, FAA's Herndon Command Center and FAA headquarters knew
two aircraft had crashed into the World Trade Center.They knew American 77
was lost. At least some FAA officials in Boston Center and the New England
Region knew that a hijacker on board American 11 had said "we have some
planes." Concerns over the safety of other aircraft began to mount.A manager at
the Herndon Command Center asked FAA headquarters if they wanted to order
a "nationwide ground stop." While this was being discussed by executives at FAA
headquarters, the Command Center ordered one at 9:25.
The Command Center kept looking for American 77. At 9:21, it advised the
Dulles terminal control facility, and Dulles urged its controllers to look for pri-
mary targets. At 9:32, they found one. Several of the Dulles controllers
"observed a primary radar target tracking eastbound at a high rate of speed" and
notified Reagan National Airport. FAA personnel at both Reagan National and
Dulles airports notified the Secret Service. The aircraft's identity or type was
Reagan National controllers then vectored an unarmed National Guard C-
130H cargo aircraft, which had just taken off en route to Minnesota, to iden-
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