Nonsens ?
Today I learned three new things:
1) Thai primary radar painted MH370 heading SW (new information, previously it was W) minutes after transponder loss => could mean MH370 wanted to return to KUL, with heading roughly 200°.
2) The NTSB seems to be convinced MH370 went "southward" to antartica with heading roughly 200° (as of routes depicted in search areas of AMSA charts).
3) If in track mode the FMC runs out of way points, i.e it reaches the last way point and no further way point is programmed the a/c falls back into HDG mode with heading previously set.
So if MH370 went to IGREX in track mode (why?), and that was the only/last waypoint programmed, it would then fall into HDG mode. Maybe HDG was still set to 200° from the previous attempt to return to KUL. That would be consistent with MH370 ending up where AMSA is looking for it.