[crazytony]

Agreed. And ADS is mandated in commercial aircraft. It's part of the system that prevents aircraft from colliding with each other in the air (TCAS/ACAS).

But as I understand in this situation they were not out of ADS-B range nor were they out of radar range. While ADS-B requires the aircraft to transmit, radar does not.

An example of an in-flight breakup happened in 2002 when China Airlines 611 which broke into 4 pieces about 40km off of an island. Looking at the radar returns they found the aircraft broke into 4 large chunks and they were able to tell where items would be due to the radar tracks.

I'm really not sure what's happened here but my hunch is that the incident happened at the boundary of one or more countries' radar systems. So Malaysia needs Vietnam and/or Thailand and/or Cambodia and/or China to turn over their radar returns so that everything can be lined up correctly.

If it was all within one radar system you would have a location pinpointed within an hour.