•  Eighteen low altitude sectors. [Figure 2-9]  •  Seven intermediate altitude sectors. [Figure 2-10]  •  Sixteen high altitude sectors. [Figure 2-11]  •  One ultra high altitude sector. [Figure 2-12]  2-6  Figure 2-13. Air Route Traffic Control Centers and sector frequencies.  controller can also display a route line for any given aircraft  on his or her radar screen. This tells the controller where  a particular aircraft is in specified number of minutes, as  well as the path the aircraft will fly to get there. Decision  support tools such as these help each controller look ahead  and avoid conflicts.  The CFRs require the pilot in command under IFR in  controlled airspace to continuously monitor an appropriate  Center or control frequency. When climbing after takeoff,  an IFR flight is either in contact with a radar-equipped local  departure control or, in some areas, an ARTCC facility. As  a flight transitions to the en route phase, pilots typically  expect a handoff from departure control to a Center  frequency if not already in contact with the Center.  The FAA National Aeronautical Information Services  publishes en route charts depicting Centers and sector  frequencies. [Figure 2-13] During handoff from one Center  to another, the previous controller assigns a new frequency.  In cases where flights may be out of range, the Center  frequencies on the face of the chart are very helpful. In  Figure 2-13, notice the boundary between Memphis,  Tennessee and Atlanta, Georgia Centers, and the remote  sites with discrete very high frequency (VHF) and ultra high  frequency (UHF) for communicating with the appropriate  From one to three controllers may work a sector, depending  upon the amount of air traffic. Each controller is assigned  to work the positions within an area of specialization.  Controllers have direct communication with pilots, with  surrounding sectors and Centers, plus the towers and Flight  Service Stations (FSS) under their jurisdiction. Each control  position is equipped with computer input and readout  devices for aircraft flight plan data.  The Center controllers have many decision support  tools (computer software programs) that provide vital  information to assist the controllers in maintaining safe  separation distances for all aircraft flying through their  sector. For example, one tool available allows the controller  to display the extended route of any aircraft on the radar  screen called a vector line. This line projects where the  aircraft will be within a specified number of minutes,  assuming the aircraft does not change its course. This is  a helpful tool to determine if aircraft flying intersecting  routes pass safely within the separation standard, or if they  conflict with each other. In addition to vector lines, the  In-flight Requirements and Instructions  NOT FOR NAVIGATION MEMPHIS Hun tsville 120.8 307.0 $_{A}$TLANT A $_{Cha}$ttanooga 132.05 353.8 MEMPHIS A TLANT A