Formulate clearances and control instructions to aircraft and vehicles on the movement area.
FAA Order JO 7210.3, Para 3-6-2, ATC Surveillance Source Use.
Position aircraft and vehicles using the movement area.
Determine the exact location of aircraft and vehicles, or spatial relationship to other aircraft/vehicles on the movement area.
Monitor compliance with control instructions by aircraft and vehicles on taxiways and runways.
Confirm pilot reported positions.
Provide directional taxi information, as appropriate.
TURN (left/right) ON THE TAXIWAY/RUNWAY YOU ARE APPROACHING.
Do not provide specific navigational guidance (exact headings to be followed) unless an emergency exists or by mutual agreement with the pilot.
NOTE: It remains the pilot's responsibility to navigate visually via routes to the clearance limit specified by the controller and to avoid other parked or taxiing aircraft, vehicles, or persons in the movement area.
Do not allow an aircraft to begin departure roll or cross the landing threshold whenever there is an unidentified target/track displayed on the runway.