On Aug 16, 4:41*pm, Mike Schumann
wrote:
On 8/16/2010 4:22 PM, noel.wade wrote:



On Aug 16, 1:49 pm, wrote:

As I understand it, Power Flarm will incorporate ADS-B ( protocall not
completely clear to me) as well as transponder PCAS annunciation.

Here's a short Not-Totally-Technically-Accurate-But-Close-Enough
Explanation:

There are two "flavors" of ADS-B: *1090ES and UAT. *The 1090ES system
is more likely to be used by big/fast airplanes. *UAT is more likely
to be equipped on small GA aircraft. *PowerFLARM supports 1090ES. *It
does not support UAT or ground-based relays of traffic information
(according to the specs released so far). *So you'll see some ADS-B
aircraft with the PowerFLARM; but you won't necessarily detect _every_
ADS-B aircraft. *I believe that "some" ADS-B detection is better than
"none", especially when you add in the ability to see Mode C/S
transponders (when replying to radar pings) and other FLARM-equipped
gliders.

--Noel
(who will have a PowerFLARM this fall)

PowerFlarm is ADS-B In only. *It only transmits FLARM, which jets can't
see. *By itself it does absolutely nothing to protect us against
mid-airs against jets.

--
Mike Schumann

Mike, what is your agenda? You seem determined to trash the potential
right-now benefits of PowerFlarm for the dubious future advantage (to
glider pilots) of ADS-B (specifically the REALLY stupid UAT part of
it). Worried about an airliner hitting you and not smart enough to
look out the window when PCAS tells you there is a big jet nearby? Get
a Mode S transponder. Or you can look at a chart and figure out the
arrival and departure routes of the local airlines and look in that
direction when you get a PCAS warning! Ditto lightplanes - they are
most likely cruising at VFR or IFR hemispheric altitudes, so if the
relative alitude is not changing, look in that direction! (Unless your
altimeter is set to QFE, of course....) What I want a FLARM device
for is to warn me of the not so random presence of other GLIDERS!

Here is a simple mental exercise: 2 power planes takeoff from the
same airfield. No coordination between the two. What is the
probability that they will have a midair? Now, two glider launch from
that same airfield, on a good soaring day. What is the probability
that they will have a midair? Let's see, the power planes have all
day to pick a time to go, and they can go in any direction, at pretty
much any altitude, to pretty much any destination. OTOH, the gliders
will likely launch at about the same time, and go the the best lift,
fly in the same altitude band, and return at roughly the same time.
THATS WHY ADS-B IS LESS IMPORTANT TO GLIDERS THAN FLARM!

And on the ridge on a good day? Yikes!!! 200knot closure, 50 feet
above the trees. Yeah, ADS-B is going to be lots of help there!

But here is a question: PowerFlarm claims it can detect ADS-B 1090ES
signals and provide bearing/rangealtitude info; it's just the legacy
Mode C transponders that will only give a range/relative altitude
warning (similar to PCAS). Are you saying that this is not possible
and that you also need a UAT in/out box to detect Mode -S equipped
1090ES ADS-B participants? I understand that with only a Powerflarm
you won't see UAT - only participants - but since they will probably
still need Mode C even that isn't true - you are just down to PCAS
level of detection. Please correct me if I'm wrong on this.

Finally, all this reminds me of my days sailing a Laser in the
Intercoastal waterway - sure I had right of way over the big barges
in the shipping channel, but no way was I going to push it! Ditto
airliners. If you are so clueless that you miss an airliner coming at
you on a VFR day, when you should know where he is coming from, and
have a 5 or more mile warning from your PCAS or PowerFlarm, you
shouldn't be flying there! Or just pony up for a Trig and be done
with it!

Finally, how about SSA working on the insurance companies to give
pilots who fly with anti-collision devices and transponders a break on
their insurance? I read somewhere Italy does that for FLARM. A 10%
reduction on my annual premium would go a long way!

Rant off/

Kirk
66
Saving my pennies for a PowerFlarm for next season (and a Trig in the
future) but not holding my breath for UAT or ADS-B