Alps crash jet pilot 'was locked out of cockpit'

One of the pilots of the crashed Germanwings jet can be heard in a 'black box' recording leaving the cockpit, then banging on the door with increasing urgency in an unsuccessful attempt to get back in, a US newspaper report has suggested.

The mangled device recovered from the wreckage of has yielded sounds and voices, but not the "slightest explanation" of why the plane crashed on a mountain in the southern French Alps, killing all 150 on board, investigators have said officially.