Originally Posted by
mcoates
If there was just two seconds either way with either aircraft, 20 feet different in altitude, then we wouldn't have had this accident.
It terrifies me that there are probably a
lot of near-misses where they do have that few-second/20ft gap - and they're never noticed, never reported, or possibly just never made public. This one just happened to not have that gap.
I've had one incident in VFR where Melbourne Centre called to say that someone was heading straight towards me at the same altitude (I was heading just about due north at 4500ft, they were heading just about due south at 4500ft). Even after that call I never managed to spot the other plane, so I can't tell how close we were - but without that call it could have been very close indeed.