I will start by stating that I don't KNOW and no one except the relevant military air defence operations centre will be able to tell you how they KNOW.
Originally Posted by
buttrick
Have I missed it somewhere? How do they Know :
A. The radar tracks WERE 370 without IFF
Please do not de-bunk unless you KNOW and can give the evidence!
What I can say is how they should have known.
The air defence centre is responsible for compiling a recognised air picture in its AOR. A civilian aircraft entering the AOR will be wearing a civil squawk which will display adjacent to the primary radar return on the military radars. Now assuming the squawk decode and its position in the airway structure correlate with a known civil flight it will be allocated a Friendly track number - this is an AD assignment and not exchanged with the civil ATC (unless they are co-located).
If the aircraft then 'strangles its parrot' (
) this will not affect the allocated track number. As the aircraft leaves the airway structure it will continue to 'wear' the same track number.
Should this aircraft then depart the relevant AOA it can be handed off to the adjacent Air Defence Centre, in this case that would be Thai
if a bilateral agreement existed but we have not heard of such bilateral liaison.