Yes after a quick scan through I thought a lot of the figures were
familiar (changed the old Hawk to an F18, though).
And further to Wombat's third paragraph the BASI report came out at a
time, if my memory is somewhat correct, when there was a change in radio
procedures and a greater reliability on radio separation was being
recommended by BASI/CASA or whoever they were at the time. There was
some small controversy at the time and I admit that I was on the side of
"see and avoid" trumps radio. Even recall having arguments with at least
one local aeroclub pilot.
I notice since that report originally came out though, "see and avoid"
has morphed into "unalerted see and avoid". This was due, I think, to
the disparaging that "see and avoid" got from this particular report and
the subsequent reliability on radio _alone_ which followed in the
subsequent years.
Note also that I am not saying that the report is factually wrong, it is
a good collection of research and does show some real limitations of
human vision. The problem was that, at the time, it was used as a sledge
hammer and the alternate reliance on radio also had significant
limitations which, just as Wombat noted, were never acknowledged.
Regards
SWK
Mike Cleaver wrote:
That is the ATSB report from 18 years ago - rather dated but of some
relevance.
You can also download the original from the ATSB web site at
http://www.atsb.gov.au/publications/1991/limit_see_avoid.aspx in PDF
format - so this may be a less bulky way for those with dial-up to
obtain and print it.
Unfortunately they never published a report on the limitations on use
of radio for collision avoidance - and hopefully we all know that
FLARM is never intended to be used as a primary collision-avoidance
tool but only as a last-resort defence when radio and lookout have
already failed to reduce the collision risk. It only gives a maximum
of 25 seconds warning of an impending near-collision, and often less
than 10 seconds. Just the same as TCAS for faster aircraft, it is a
last line of defence and gives an idea of where to look to see the
collision threat, if you have time!
Wombat
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