Most of the location information to date has been provided by Inmarsat. The potential accuracy of position data from this source has been questioned. So how can we know the most probable search areas?
First, lets look at data that has the potential to be accurate;radar. There are two kinds of radar of interest in this case. First there is air traffic control (ATC) radar. This type displays position of aircraft. Altitude data is not provided unless the aircraft being tracked has a transponder. The transponder provides information which includes altitude, flight number and ground speed. Other parameters may also be transmitted along with the radar “blip”.
If the aircraft does not have a transponder, or it is turned off, the radar return is known as a “skin paint” This is what is usually described as a “blip”. No altitude data is available.
The other type of radar is one used by the military for defense purposes. It is capable of determining altitude from a skin paint, a reflection off the aircraft surfaces. Military radar would be available to all nations in the vicinity to the north and west of Malasia. The maximum range for a skin paint of these radars would depend on the elevation of the antenna and the altitude of the airplane. For example, if the radar antenna was at sea level and the airplane was at thirty five thousand feet the range might be on the order of 250 miles. The range wold also be dependent on size of the aircraft, power of the radar and weather obstructions.
The various tracks shown by the media indicate the initial track toward Bejing and the left turn.The southerly track to the Indian Ocean has been provide by Inmarsat. This data has ben questioned as to the methodology and potential accuracy.
My personal belief is that had the aircraft turned back to the north or northwest it would have reentered the radar coverage areas for the military radars. The countries involved are very serious about their airspace and would have attempted to contact MS 370 or scramble aircraft to investigate. By eliminating a west or northwest track we fare left with a) the Inmarsat track or b) a potential track to the west or southwest toward Africa. The Inmarsat data is suspect so perhaps we should be looking to the west.