FAA Centers often receive information and make operational decisions
independent of one another. On 9/11, the four hijacked aircraft
were monitored mainly by four of these FAA Air Route Traffic
Control Centers, based in Boston, New York, Cleveland, and Indianapolis.
Each Center thus had part of the knowledge of what was going
on across the system. But it is important to remember that what
Boston Center knew was not necessarily known by the Centers in
New York, Cleveland, or Indianapolis.
Controllers track airliners like the four aircraft hijacked on
9/11 primarily by watching the data from a signal emitted by
the aircraft's transponder equipment. The four aircraft hijacked
on 9/11, like all aircraft traveling above 10,000 feet, were
required to emit a unique transponder signal while in flight.
On 9/11, the terrorists turned off the transponders on three
of the four hijacked aircraft.
With the transponder turned off, it may be possible, although
more difficult, to track an aircraft by its primary radar returns.
A primary radar return occurs when the signal sent from a radar
site bounces off an object in the sky and indicates the presence
of that object. But primary radar returns do not include the
transponder data, which show the aircraft's identity and altitude.
Controllers at Centers rely on transponder signals and usually
do not display primary radar returns on their scopes. But they
can change the configuration of their radar scopes so they can
see primary radar returns. In fact, the controllers did just
that on 9/11 when the transponders were turned off in three of
the four hijacked aircraft. Tower or terminal approach controllers
handle a wider variety of lower-flying aircraft; they often use
primary radar returns as well as transponder signals.
NORAD Mission and Structure
NORAD was, and is, responsible for the air defense of the continental
United States. The threat of Soviet bombers diminished significantly
after the end of the Cold War, and the number of NORAD alert
sites was reduced. On 9/11 there were only seven left in the
United States, each with two fighter aircraft on alert.
All the hijacked aircraft were in one of NORAD's Continental
U.S. sectors, the Northeast Air Defense Sector (also known as
NEADS). NEADS is based in Rome, New York. On 9/11, it could call
on two alert sites, each with one pair of ready fighters. These
were the Otis Air National Guard Base in Cape Cod, Massachusetts
and Langley Air Force Base in Langley, Virginia.
NEADS reported to the Continental Region headquarters in Florida,
which reported to NORAD headquarters, in Colorado Springs, Colorado.
Most FAA centers had a civilian employee to coordinate with NORAD,
for situations like training exercises. The agencies had also
developed protocols for working together in the event of a hijacking.
As they existed on 9/11, the protocols for the FAA to obtain
military assistance from NORAD required multiple levels of notification
and approval at the highest levels of government.
FAA guidance to controllers on hijack procedures assumed that
the aircraft pilot would notify the controller of the hijack
via radio communication or by 'squawking' a transponder code
of '7500'?-the universal code for a hijack in progress. Controllers
would notify their supervisors, who in turn would inform management
all the way up to FAA headquarters in Washington. Headquarters
had a 'hijack coordinator' who was the Director or his designate
of the FAA Office of Civil Aviation Security.
If a hijack was confirmed, procedures called for the hijack coordinator
on duty to contact the Pentagon's National Military Command Center
(NMCC) and to ask for a military 'escort aircraft' to follow
the flight, report anything unusual, and aid search and rescue
in the event of an emergency. The NMCC would then seek approval
from the Office of the Secretary of Defense to provide military
assistance. If there was approval, the orders would be transmitted
down NORAD's chain of command and direct the sector to launch
a fighter escort.
The protocols did not contemplate an intercept. They assumed
the fighter escort would be discreet, 'vectored to a position
five miles directly behind the hijacked aircraft,' where it could
perform its mission to monitor the flight path of the aircraft.
In sum, the protocols in place on 9/11 for the FAA and NORAD
to respond to a hijacking presumed that:
(1) the hijacked aircraft would be readily identifiable and would
not attempt to disappear;
(2) there would be time to address the problem through the appropriate
FAA and NORAD chains of command; and
(3) the hijacking would take the traditional form, not a suicide
hijacking designed to convert the aircraft into a guided missile.
On the morning of 9/11, the existing protocol was unsuited in
every respect for what was about to happen. What ensued was the
hurried attempt to create an improvised defense by officials
who had never encountered or trained against the situation they
faced.
The details of what happened on the morning of September 11 are
complex. But the details play out a simple theme. NORAD and the
FAA were unprepared for the type of attacks launched against
the United States on September 11, 2001. They struggled, under
difficult circumstances, to improvise a homeland defense against
an unprecedented challenge they had never encountered and had
never trained to meet.
http://www.scoop.co.nz/mason/stories/WO0406/S00204.htm
