Flarm in the US

On 8/10/2010 9:58 PM, Alan wrote:
A reasonable point. There is a lot of little used space to fly in.
As someone who started as a power pilot, I still find it hard to imagine
how one would be willing to fly in such close proximity to other aircraft
that you cannot continuously see.

"Cessna 123, traffic at your 3 o'clock, one mile, same direction" gets
my attention.

"glider 45, traffic at your 6 to 7 o'clock, 50 yards behind, 100 feet
above, circling in same direction" sounds terrifying. (I am in a blind
spot for him, and he is in one for me.)

I worry enough about a plane a mile away in a traffic pattern. Not having
continuous visual separation at 50 yards distance scares me.


Your concern is understandable, given your background, but the lack of a
motor makes circling together more predictable than attempting the same
thing with powered aircraft. Glider sink rates aren't very different
when circling, even between a high performance glider and a club
trainer, maybe 50 feet/minute. So, for each circle completed, the
altitude difference has changed only 25 feet (typical circles take 20 to
35 seconds). Also, because they are going around the circle at about the
same rate, the horizontal distance also changes slowly.

That's what makes it work: the changes in relative position are slow,
because the horizontal distances and vertical distances are changing
slowly. Another factor is visibility out of a glider cockpit: it's large
bubble canopy makes it far easier to see the other gliders than the
typical airplane cockpit allows. A very important factor is most glider
pilots have training and experience in circling together, often starting
before they have even soloed, which is not the case for airplane pilots.

Still, it is riskier than flying alone, but I don't mind doing it with
pilots I know and trust (which is most of them), and I sometimes leave
the gaggle when proper separation is too hard to maintain.
I don't think the proprietary flarm system is the answer (being a fan of
open standards).

Where's the problem? It works well, it's available relatively cheaply,
it's been available for years overseas, there are several licensed
manufacturers, and now it's coming the USA. I'd say the proprietary
nature is what makes all these things possible, as it guarantees all the
units will work with each other.
I would much prefer spending my time where the only other
traffic is likely to be a bird, and enjoying the view.

I enjoy that very much, but it is also great fun to sometimes fly with
other pilots. And, a good way to learn more about soaring well, too.

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz