Approach and Landing

When your descending plane is 50 miles from the San Francisco airport, it is within TRACON airspace. An approach controller directs your pilot to adjust the aircraft's heading, speed and altitude to line up and prepare to land along standard approach corridors. Your pilot then aligns your plane with the runway. When you are 10 miles (16 km) from the runway, the approach controller passes your plane off to the local controller in the airport tower.

Photo courtesy Federal Aviation Administration (FAA) Departure and approach corridors for eastward air traffic to and from airports in the San Francisco Bay Area TRACON airspace. (Click on the image for a larger view.)

FAST Software The approach controller uses another software program developed by NASA and the FAA called the final approach spacing tool (FAST). The FAST program assists controllers in choosing the landing order and runway for each approaching aircraft. The program does the following: Projects each aircraft's flight path based on flight plan and radar tracking Predicts arrival time Suggests landing order and runway assignment based on calculations that take into account aircraft size, aircraft performance capability and wind directions The FAST software helps to ensure that no single runway or controller gets overloaded with planes, helping to minimize unnecessary delays.

Landing
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, multimedia 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.