Ever wonder how airplanes communicate to air traffic controllers on the ground when flying over the ocean? Air traffic controllers typically track airplanes using radar technology, which is only effective for up to 200 miles offshore. After flying farther than 200 miles over the ocean, commercial airplanes are typically out of radar range. As a result, pilots must use an alternative method to communicate with air traffic controllers on the ground.

Satellites

When flying over the ocean — where they are out of radar range — pilots often rely on satellites to communicate with air traffic controllers on the ground. Satellites, of course, fly along a fixed path in Earth’s orbit. Therefore, they can send and receive data to airplanes over the ocean. As the pilot flies an airplane over the ocean, he or she will transmit their location to air traffic controllers via satellite technology.

The pilot will essentially upload the airplane’s location to the satellite, after which the satellite will relay this data to air traffic controllers on the ground. This is the most common way that airplanes communicate when flying over the ocean. With that said,  however, it’s not only the method used for overseas communication.

High-Frequency Radio

In addition to satellites, some airplanes rely on high-frequency radio technology to communicate with air traffic controllers on the ground. It’s an older and less-reliable communications technology, but it’s still used by countless airliners. High-frequency radio technology involves relaying the airplane’s location to a network of receivers, which eventually pass the data to air traffic controllers on the ground.

Traffic Collision Avoidance Systems

While airplanes typically use either satellites or high-frequency radio systems to communicate with air traffic controllers on the ground, most of them also feature a traffic collision avoidance system. Traffic collision avoidance systems aren’t used to communicate with air traffic controllers on the ground, though. They are used to communicate with other nearby airplanes for the purpose of avoiding a midair collision.

Whether an airplane it flying over land or sea, its traffic collision avoidance system will constantly emit a signal. If another airplane encroaches upon the plane’s airspace, both pilots will receive an alert. The pilots can then take the necessary actions to avoid a collision.

To communicate with air traffic controllers on the ground, pilots use either satellites or high-frequency radio systems when flying over the ocean. To prevent midair collisions, on the other hand, they use traffic collision avoidance systems.