not currently enable a constant tracking of a jet by a ground crew at all times . Planes receive a position signal , but do n't transmit that back . This is not a problem when a jet is flying over land or in coastal areas , as it is tracked by radar . Over oceans radar does not work as it relies on line-of-sight tracking from a ground station . On oceanic flights a flight crew will know its exact position via GPS , but it is not able to be tracked by air traffic control . It is left to someone in the cockpit to relay information via satellite communication to air traffic control or a ground station . `` Airlines often have a contract with a private operator to provide their satellite communications . Some companies pay for it , some have free contracts , '' Roelandt said . Modern jets equipped with an Aircraft Communication , Addressing and Reporting System -LRB- ACARS -RRB- , like the A330-200 , are also able to send automatic digital signals . These are not instigated by the crew but report automatically on the plane 's systems and relay information to
-LRB- CNN -RRB- -- Cars have Global Positioning System devices to pinpoint where drivers are when they get lost , so why ca n't GPS be used to locate the exact position of planes when the worst happens ? There is currently no way to constantly track planes as they fly over oceans . It took search and rescue teams over 30 hours to locate the wreckage of the Air France plane that crashed in the Atlantic on Monday . It appears that the aircraft 's onboard GPS system was little help to rescuers in the mission . Although details of Air France flight 447 's fate remain uncertain , in some air accidents , this critical time could mean the difference between life and death for any survivors . Michel Roelandt , aviation expert for Eurocontrol , a European air navigation safety organization , told CNN that nearly all modern planes are fitted with GPS navigation systems . How sophisticated those the communications and navigation systems are is down to individual airlines when they fit out their planes , an Airbus spokesperson told CNN . On board GPS systems are primarily navigation tools for the crew , and do