Originally Posted by
sriegert
+1. this is partly why it was difficult to locate AF447. the curvature of the earth meant that the a/c was out of contact with radar for an extended period of time.
Yep! People forget or don't know radar waves are short (well other than military stuff like PAVE PAWS), therefore are only line of sight. To have maximum range the aircraft must be high in the sky.
There may be no Area Control Centre radar between KUL and SGN (maybe TGG?), a 650 mile distance, so that leaves a lot of "hole" without coverage.