Why is tracking a missing commercial aircraft so difficult?

When something is lost like this, they call in an expert like me (obviously not me in these cases, but there are lots of similar experts). The problem is you can extrapolate a path of probability only so far. What happened? Was it on autopilot or manual control when communication was lost? If on autopilot, how far do you estimate it continued on autopilot until “something happened.”

It’s slightly easier with rockets and missiles, aircraft have wing surfaces that allow it to turn and move over a wider range. You start with a “best guess” of what happened, the more you know before making that guess the better and then you widen a search grid from that spot.

GPS is a passive location system. The GPS satellites are all sending signals to a GPS receiver located on the aircraft; a processor in the GPS device translates all the signals from visible satellites into an estimate of position. That position is then forwarded by telemetry signal, for as long as the telemetry transmission is continuing, to ground stations and sometimes satellites to pick up the location signal. That part is active. When you hear someone say “we lost communication” or “we lost the signal” if there were no radars on that vehicle, there is no more position. The pilot still knows where they are, but what happened?

That what is the key to finding a down aircraft. If you guess right you up your chance of finding the vehicle significantly. If you guess wrong… the pilot could lose an engine and go into a hard turn. How hard? Did they try to search for an emergency landing spot? where did they search? where did the pilot go? Why? What happened?