曝光台 注意防骗
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when a flight is vectored over an airport at an altitude that
appears to enter the tower controller’s airspace, there is no
need to contact the tower controller—all coordination is
handled by ATC.
The departure radar controller may be in the same building
as the control tower, but it is more likely that the departure
radar position is remotely located. The tower controller will
not issue a takeoff clearance until the departure controller
issues a release.
Terminal Radar Approach Control (TRACON)
TRACONs are considered terminal facilities because they
provide the link between the departure airport and the en route
structure of the NAS. Terminal airspace normally extends 30
nautical miles (NM) from the facility, with a vertical extent
of 10,000 feet; however, dimensions vary widely. Class B
and Class C airspace dimensions are provided on aeronautical
charts. At terminal radar facilities the airspace is divided
into sectors, each with one or more controllers, and each
sector is assigned a discrete radio frequency. All terminal
facilities are approach controls and should be addressed
as “Approach” except when directed to do otherwise (e.g.,
“Contact departure on 120.4”).
Terminal radar antennas are located on or adjacent to the
airport. Figure 9-7 shows a typical configuration. Terminal
controllers can assign altitudes lower than published
procedural altitudes called minimum vectoring altitudes
(MVAs). These altitudes are not published or accessible to
pilots, but are displayed at the controller’s position, as shown
in Figure 9-8. However, when pilots are assigned an altitude
that seems to be too low, they should query the controller
before descending.
When a pilot accepts a clearance and reports ready for takeoff,
a controller in the tower contacts the TRACON for a release.
An aircraft is not cleared for takeoff until the departure
controller can fit the flight into the departure flow. A pilot may
have to hold for release. When takeoff clearance is received,
the departure controller is aware of the flight and is waiting
for a call. All of the information the controller needs is on
the departure strip or the computer screen there is no need to
repeat any portion of the clearance to that controller. Simply
establish contact with the facility when instructed to do so by
the tower controller. The terminal facility computer picks up
the transponder and initiates tracking as soon as it detects the
9-7
assigned code. For this reason, the transponder should remain
on standby until takeoff clearance has been received.
The aircraft appears on the controller’s radar display as a
target with an associated data block that moves as the aircraft
moves through the airspace. The data block includes aircraft
identification, aircraft type, altitude, and airspeed.
A TRACON controller uses Airport Surveillance Radar
(ASR) to detect primary targets and Automated Radar
Terminal Systems (ARTS) to receive transponder signals; the
two are combined on the controller’s scope. [Figure 9-9]
At facilities with ASR-3 equipment, radar returns from
precipitation are not displayed as varying levels of intensity,
and controllers must rely on pilot reports and experience
to provide weather avoidance information. With ASR-9
equipment, the controller can select up to six levels of
intensity. Light precipitation does not require avoidance
tactics but precipitation levels of moderate, heavy or
extreme should cause pilots to plan accordingly. Along
with precipitation the pilot must additionally consider the
temperature, which if between -20° and +5° C will cause icing
even during light precipitation. The returns from higher levels
of intensity may obscure aircraft data blocks, and controllers
may select the higher levels only on pilot request. When
uncertainty exists about the weather ahead, ask the controller
if the facility can display intensity levels—pilots of small
aircraft should avoid intensity levels 3 or higher.
Tower En Route Control (TEC)
At many locations, instrument flights can be conducted
entirely in terminal airspace. These TEC routes are generally
for aircraft operating below 10,000 feet, and they can be
found in the A/FD. Pilots desiring to use TEC should include
that designation in the remarks section of the flight plan.
Pilots are not limited to the major airports at the city pairs
listed in the A/FD. For example, a tower en route flight from
an airport in New York (NYC) airspace could terminate
at any airport within approximately 30 miles of Bradley
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Instrument Flying Handbook仪表飞行手册下(61)
