Air Traffic Control

PJ Wellspring of Whitstable, ex RAF pilot, then RAF and civil Air Traffic Controller
gave us a talk entitled ‘Radar & Radio in support of Air Traffic Control’
To illustrate the problems faced by the controller he showed us a map of Heathrow
with the incoming and outgoing flights, then gradually zoomed out showing the complexity of flights going to other airports in the UK and Europe with Heathrow dealing with over 1300 flights a day. The controller has to keep planes separated in altitude by 1000 feet, note the imperial measurements and 5 nautical miles apart. The UK was first to start commercial flights from Croydon in 1920. While the US started later, we are stuck with their system of Airways or defined routes. They wanted mail to go through the night from San Francisco to New York and lit bonfires every 10 miles to guide the planes. They also painted 70 ft arrows across the country!

PJ explained the the principles of primary and secondary radar. Each plane now carries a transponder which places an image at its location on the controller’s radar map and gives information as to its identity, heading, altitude and speed. It also sends a coded message, eg ‘7700’ for ‘Emergency.
If you would like to track planes go to RadarBox24 or live download app Flight Radar 24. It was a very interesting talk. Thank you PJ.