In this project, we analyzed data collected by the OpenSky Network in September 2015. This data set consists of messages sent by the planes themselves. There are different message types that transmit either part of the current position of the plane, information about the current movement, information about the current call sign of the plane or other information. In the data, we looked for planes that fly holding or do go-arounds.

Unfortunately, the data available to us has some limitations:

• Antennas don't pick up signals from planes which fly close to the ground. That includes planes in the later stages of their approach to an airport.
• Data coverage is limited to certain parts of Central Europe, please see the map below. There is no data when the plane is outside the blue area.

Therefore, our results are limited to airports in the coverage area. The closer the airport to the next antenna (red in the map below), the better the data quality. For example, Paris and Munich Airports are both right at the border of the coverage area, so we are missing planes approaching from angles not in coverage. And even for planes approaching from covered areas, data is getting more sparse the further the plane moves away from an antenna. Even more so, when it is flying at a low altitude.

But for airports like Frankfurt Main or Amsterdam Schiphol, we have excellent data, as they are very close to antennas.

OpenSky coverage: sample of received data points in blue, OpenSky antennas in red

You either read or scrolled through the about page. Respect! Here is a little gimmick for you, a 3D visualization of plane positions in one of the major London holding stacks: Bovingdon.