On 06/25/2013 02:45 PM, David Joyce wrote:
> One minor cautionary tale about Powerflarm type systems.
Nobody suggest that you don't have to look yourself anymore.
Until now I had a mode-C based traffic detector. Although I always fly
with my wife and we are both pilot, and have the rule that only one of
us looks at the map/instuments at a time so there is always at least one
pair of eyes outside, most of the traffic is spotted earlier by the
traffic watch than by us. It is stunning how much traffic we simply miss
and never would have noticed without traffic watch. Only in a very minor
amount of cases it is the other way around. In these cases it is often
"something" without transponder, or low flying in mountenais terrain
where the radar interrogation doesn't reach the transponder, or when
there is too much traffic around and the traffic watch focusses on the
wrong (further away) aircraft. These failures are mostly due to the
nature of mode-C detection, but with Flarm, ADS-B and mode-S the
detection rate and accuracy will be much better. (too bad that in the UK
it is not allowed to use the ADS-B capability of your transponder, but
in most other countries more and more people are using it. For those who
don't know what it is: wth ADS-B the transponder not only broadcasts the
altitude but also the GPS coordinates, giving a highly accurate 3D
position of the aircraft. Advanced computations can then calculate
whether a nearby aircraft is a potential threat or not, similar to the
Flarm system).
Frans
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