It may have fallen off the radar but there were plenty of spy satellites around.
If it exploded, you know one of the satellites watching the south western pacific would have seen the flash and the heat signature.
I wish they would just say, yup...it blew up. Russia knows. China knows. And I am sure Australia knows.
The NSA knows when I relax my bowels. A plane blows up and no one knows?
Not buying it.