In light of the Malaysia Airlines Flight 370 disappearance, Absolute News wanted to describe how planes are tracked by air traffic controllers. Malaysia Airlines uses a satellite tracking system as do all airlines and airplanes. There are several major and required equipment on all commercial aircraft that help pilots and controllers on the ground avoid crashes, avoid mid-air collisions, and provide maintenance data on the airplanes while in flight. These systems are radar, transponder, TCAS, and ACARS. Flight 370 had it’s equipment turned off in the cockpit about 1 hour into the flight and after its last voice communications with the pilots. Then based on radar data, the plane turned sharply and eventually radar contact was lost. After radar contact was lost, the ONLY way we know the direction of the airplane is due to satellite “hand-shakes”. The satellites “saw” that a plane was in their “view” and try to communicate, or hand-shake, with the ACARS equipment but the satellites didn’t get a response. It did, however, leave a digital footprint showing there was an attempt to hand-shake.
To turn off the ACARS equipment is not a simple task nor something done out of normal routine and training. So, whoever turned it off not only new about this system and how to do it, but likely had studied, trained, and practiced. CNN’s aviation expert Richard Quest said “the ACARS stopped communicating sometime between 1:07 and 1:37 a.m. It’s a significant event: Turning off ACARS takes know-how. If the flight were hijacked or a target of terrorism, cutting off ACARS would be a strategic move because the system reports to satellites anything being done to the aircraft,” (CNN 1:37am mark)
Even with these satellite tracks, there is still huge discrepancy over which direction the plane headed: North or South. (See our story on the flight path.)
Here’s a quick and simplified overview of the various equipment and systems used to track commercial airplanes.
Radar: Most everyone is familiar with radar where a radio wave is sent from a tower through the sky and any large object this wave hits, is bounced back to the radar tower. This leaves a blip, a dot, on the radar computer screen. That’s all. Anyone looking at this screen would not know what the object is, how high it is, but could tell the direction it is headed. (more info)
Transponder: A Transponder is a device on board all commercial airplanes that sends out a signal to Air Traffic Control (ATC) towers alerting the controllers to the airplanes altitude. A transponder code assigned by ATC before takeoff is used to identify which aircraft it is. This information is paired with the radar blip to give ATC more information about the aircraft. (more info)
ACARS: The Aircraft Communications Addressing and Reporting system is used to send flight information from the plane to the airline’s ground computers. Also the ground computers send data to the planes on weather and other updates. The transmission between the plane and the ground computers is sent either by ground based antennas or by satellite. (more info)
TCAS: The Traffic Collision Avoidance System is an electronic system on all commercial airline planes that help pilots avoid other planes while flying. This system sends out signals and any airplanes in the area respond with their own signal. This allows the planes to communicate and share their locations. If the TCAS computer thinks a possible collision might occur, warnings are given to the pilots so they can investigate and change course if necessary. (more info)