As you may know, on the internet there is the FlightRadar24 website where you can see the flight information of planes worldwide in real time. Although this is wonderful for those who like aviation, does this type of system not pose any risk to aircraft safety? For example, terrorists may well plan an attack on a specific plane by knowing its information.
The short answer is yes it does. In reality, the amount of benefit Flight Radar gives to those that would exploit it for evil is negligible compared to the amount of good the technology provides.
The data for Flight Radar is drawn from ADS-b transceivers. It will only provide the present and historical position of the flight. The aircraft’s future position can only be speculated upon based on its flight plan. If a flight’s position is classified or of concern for national security, the ADS-b information will not be broadcast “in-the-clear”.
As far as terrorism, Flight Radar will not provide any more information than a good network of plane spotters would. After all, a cruising altitude of over 30,000 feet MSL would make all but the most advanced military equipment ineffective against a commercial aircraft. Below cruising altitude, line-of-sight weapons would make Flight Radar redundant to common binoculars and scopes. Terrorists aboard an aircraft would make Flight Radar a non-issue. Not to mention, the terrorists would probably try to turn off the transponder and ADS-b.
A similar argument was made for the use of GPS when it was first created. That is why the accuracy was purposefully limited by the government for the adoption by the civilian market.
Plane movements are, for the most part, planned well in advance. Not only that, an airline actually has to publicize those times in order for customers to be able to book tickets. Want to find what times EasyJet is flying from London to Paris? Look on their website!
The only way terrorists could be helped by having position information is if they had a surface-to-air missile and they wanted to take out a specific aircraft. However in that case they would have to be somewhere on the flightpath for takeoff or landing in order to have a shot. And in that case they can simply listen to the radio between ATC and the various aircraft to find where they are.
So it doesn't add any extra risk that isn't already there.