On Fri, 28 Nov 2003 18:25:33 +1100, Andrew Rowley
wrote in Message-Id:
:

they don't like the idea of uncontrolled VFR in "their" airspace.

"Larry Dighera" wrote in message
...

Why? Are they unaccustomed to keeping a visual watch for conflicting
aircraft? Don't they possess the qualifications of US pilots and
controllers who seem to manage without difficulty? I don't get it.
It seems to reveal some sort of elitist thinking.

The concept of class E airspace is based on the premise that see-and-avoid
is an effective means of separation in VMC.

However, that effectiveness is bound to vary with aircraft speed, and most
models of visual acquisition indicate that the effectiveness falls
dramatically as speed increases. The FAA evidently acknowledged that with
its introduction of TCAs (now class B) and PCA (now class A above FL180).
To external observers it does seem odd that the FAA forces transport
aircraft to share its airspace with uncontrolled VFR from the base of class
A to the top or lateral boundaries of class B.

The justification for having class E rather than class A or B is that the
traffic density is sufficiently low that the probability of conflicts is
very small, not that pilots are able to overcome the limitations of human
perception with some sort of 'visual acquisition qualification'.
See-and-avoid is clearly not considered to be good enough in the higher
traffic-density airspace.

Whether the Australian commercial pilots' gripes are justified would seem to
revolve around the details -- the traffic density in the airspace that has
been downgraded -- not a judgement of whether the principle of wanting a
more controlled class of airspace is 'elitist'.

Julian Scarfe