"Do It Yourself" airborne proximity warning device

On Wednesday, December 11, 2013 9:07:33 AM UTC-8, Dan Marotta wrote:

But, like anything aviation related, it would probably cost both arms and
legs.

Maybe someone should develop a device like the MRX PCAS which detects
transponders and includes azimuth in addition to range and elevation.

Thanks for the info on the ASDE-X system Dan - I think you are right that it's unlikely to make a cost-effective anti-collision system in the end.

I think Sarah's link to the Zaon XRX represents an attempt at what you are talking about that only costs one arm. It carried a retail price of $1395.. Even if it were in production today I'd still rather carry a PowerFlarm for that kind of money because you'd get actual 1090ES GPS fixes plus PCAS plus glider Flarm traffic for about the same price. I think in general the idea of trying to interpret radar returns - even with a lot of calculus of variations math - is by now antiquated and far inferior to more modern GPS-based solutions. The review on the XRX seemed to confirm this - it only sometimes worked.

I looked up ABQ in the FAA's Air Traffic Activity System. On an average summer weekend soaring day it handles about 100 total airport operations during the active soaring day, which places it at #116 among airports in the US - a reasonably busy airport. Even so, I'd bet dollars to donuts that if you took all the IGC traces and all the radar traces and compared them you'd find on a typical glider flight that more than 9 out of 10 of the closest approaches to another aircraft would be another glider or towplane, not a commercial jet.

That's not to say I'm advising against a transponder - I often fly near Reno (#197 in summer weekend airport operations) and I carry one. Yes there are differences across airports in terms of how the jet approaches mix with glider flights. However - if we take it back to actual statistics, I expect ABQ is not so atypical a traffic situation to overcome the more than 10x difference in the statistics on average - that is, you are more than 10x as likely to run into another glider or local traffic at your home airport than a jet. The big jets are certainly more obvious and scarier and would make a bigger headline if you actually hit one, but the outcome for you is the same whether you smash into one of those or your soaring buddy. For that reason I consider carrying a transponder more of a public service than my primary device for personal safety - my PowerFlarm, InReach, parachute and extra drinking water all rank ahead of my transponder in terms of personal safety - more or less in that order.

9B

There seems to be a misunderstanding of the Moriarty flight environment.
We're a good 40 miles east of ABQ, on the other side of the mountains from
them, in fact.

East bound departures from ABQ generally start out north or south on the
west side of the mountains and transition to the east after 20-30 miles.
Arrivals, on the other hand, fly directly over Moriarty at about 14,000' MSL
(8,000' AGL).

Most glider flights here head north, east, or south. We do go west,
generally up to the mountains, but don't often cross. Of course we can,
it's just that we have great flying on the east side and, to the north, can
get on the range that goes up to Colorado and beyond.



wrote in message
...
On Wednesday, December 11, 2013 9:07:33 AM UTC-8, Dan Marotta wrote:

But, like anything aviation related, it would probably cost both arms and
legs.

Maybe someone should develop a device like the MRX PCAS which detects
transponders and includes azimuth in addition to range and elevation.

Thanks for the info on the ASDE-X system Dan - I think you are right that
it's unlikely to make a cost-effective anti-collision system in the end.

I think Sarah's link to the Zaon XRX represents an attempt at what you are
talking about that only costs one arm. It carried a retail price of $1395.
Even if it were in production today I'd still rather carry a PowerFlarm for
that kind of money because you'd get actual 1090ES GPS fixes plus PCAS plus
glider Flarm traffic for about the same price. I think in general the idea
of trying to interpret radar returns - even with a lot of calculus of
variations math - is by now antiquated and far inferior to more modern
GPS-based solutions. The review on the XRX seemed to confirm this - it only
sometimes worked.

I looked up ABQ in the FAA's Air Traffic Activity System. On an average
summer weekend soaring day it handles about 100 total airport operations
during the active soaring day, which places it at #116 among airports in the
US - a reasonably busy airport. Even so, I'd bet dollars to donuts that if
you took all the IGC traces and all the radar traces and compared them you'd
find on a typical glider flight that more than 9 out of 10 of the closest
approaches to another aircraft would be another glider or towplane, not a
commercial jet.

That's not to say I'm advising against a transponder - I often fly near Reno
(#197 in summer weekend airport operations) and I carry one. Yes there are
differences across airports in terms of how the jet approaches mix with
glider flights. However - if we take it back to actual statistics, I expect
ABQ is not so atypical a traffic situation to overcome the more than 10x
difference in the statistics on average - that is, you are more than 10x as
likely to run into another glider or local traffic at your home airport than
a jet. The big jets are certainly more obvious and scarier and would make a
bigger headline if you actually hit one, but the outcome for you is the same
whether you smash into one of those or your soaring buddy. For that reason I
consider carrying a transponder more of a public service than my primary
device for personal safety - my PowerFlarm, InReach, parachute and extra
drinking water all rank ahead of my transponder in terms of personal
safety - more or less in that order.

9B