The local controller in the airport tower checks the runways and the skies above the runways with binoculars and surface radar (local and ground controllers are the only controllers licensed to use visual information in performing their duties). When the local controller determines that it is safe, he or she gives your pilot clearance to land. The local controller also updates weather conditions for your pilot and monitors the spacing between your plane and other landing aircraft.
Photo courtesy NASA
Air traffic controllers in the tower monitor takeoffs, landings and ground traffic with visual and radar tools.
Once you've landed, the local controller directs your plane to an exit taxiway, tells your pilot the new radio frequency for the ground controller and passes your plane off to the ground controller.
The ground controller watches the runways and taxiways and uses ground radar information to ensure that your taxiing aircraft does not cross active runways or interfere with ground vehicles. He or she directs your plane to the appropriate terminal gate. Ground personnel from the airline use hand signals to assist your pilot in parking the airplane at the gate.
Gate to Gate CD-ROM
NASA Ames Research Center and the FAA have released an excellent, educational, multi-media CD-ROM entitled "Gate to Gate" that explains modern air traffic control. There is also an accompanying Student Activity and Career Guidance Package that teachers can use. You can request the free CD-ROM by contacting Karen Stewart at the FAA.