rtdf4. the aircraft was within radar range of possibly half of java during its transit past the island. I believe the assumption is that it turned south at or around anoko ( fir bdy) and continued down longitude E94 degrees 25 minutes. he would have passed 60 nm abeam of banda aceh, 110 nm from the coast at latitude N4 deg, 243nm from the coast at lat N2 deg, 312nm from the coast at equator and 585nm from coast at S6 deg when clearing southern end of java.
he would have crossed 15 air routes while passing java and another 5 further south. they led to and from malaysia indonesia and australia. if someone was still in control they would presumably have switched off all visible lighting so chances of being seen not high.
I think australian atsb would have been very keen to have some radar contact to back up the inmarsat info before embarking on their immense search. guesswork of course but it must be possible that indonesia discovered the aircraft had passed them when they played the tapes back much later. they would tell australia in confidence who now have the corroborative evidence they needed and press ahead.