snarek
Let me prefix this with the following disclaimer: I know no more about the ML incident than is general knowledge within the place I work. I have no inside knowledge of this particular incident.
My understanding is, in E, ATC provides separation to IFR and advisory on VFR.
Not quite. We provide traffic information (as opposed to advisory) on VFR. An advisory service is a higher level of service and is not a feature of Class E.
So by turning the Cessna s/he had 'taken control'
A controller only has ‘control’ of an aircraft when it is subject to a clearance. Thus, a controller in Class E can suggest a heading to a VFR aircraft – perhaps in order to facilitate a clearance and
later control. (i.e. “A clearance is not available in your current position – but if you fly heading XXX it will be”)
and on that basis I can only assume was providing IFR/IFR separation.
This is where your assumption leads you to incorrect conclusions. IFR/IFR separation would have been 1,000FT. Stopping the B737 at FL180 did not achieve (nor is there any evidence to suggest it was intended to achieve) IFR/IFR separation.
Now I have absolutely no problems with that, that is the 'culture' everyone says we don't have in Oz. It is just that if it is true, then it is not a breakdown of NAS.
I am by no means suggesting that there was a ‘breakdown of NAS’. This appears to be
exactly what NAS was designed to achieve. I just don’t think that 500FT with no lateral (or 400ft with 1NM according to some unconfirmed sources) between a B737 and a C421 with the inevitable resultant TCAS climb is what I want to base a ‘safe, orderly and expeditious’ flow of air traffic upon.
I contend that the previous system was:
a) safer – the aircraft would all have been known to the controller and separated by at least 1,000FT or 5NM;
b) more orderly -as both the B737’s TCAS RA and the C421’s turn would not have been required; and
c) more expeditious – as a planned sequence of events would have avoided the extra fuel burn etc.
Given the above, I really shake my head and wonder what benefits we have achieved to throw away safety, money and a system that worked?