On Aug 9, 9:45*am, Mike Schumann
wrote:
On 8/9/2010 9:12 AM, Renny wrote:

On Aug 9, 7:56 am, Mike
wrote:
On 8/9/2010 8:43 AM, Steve Freeman wrote:

Curious about the use of Flarm in the US. Was told by another pilot
that the frequency used by Flarm is not approved for that category of
use in the US. Is that true? If it is, do they make units that use a
US approved frequency?

There is virtually no FLARM in the US. *It is unlikely to take off here,
as the biggest threats for mid-airs in the US are between powered
aircraft and gliders or other aircraft.

It's a chicken and egg situation. *FLARM is only interesting if everyone
equips. *No one is going to equip if they don't think that everyone else
will.

With ADS-B coming out, that is the way to go in the US. *If you buy an
ADS-B transceiver, not only will you see other ADS-B equipped aircraft,
but, if you are within range of an ADS-B ground station, you will also
see all Mode C/S transponder equipped aircraft that are visible to ATC..
* *With 80-90% of GA aircraft in the US transponder equipped, this gives
an immediate benefit to anyone investing in ADS-B (assuming that they
have a ground station deployed in their area).

--
Mike Schumann

Mike,
Your points are all well taken. I realize that FLARM has never been
accepted in the US up to now, and we all know that ADS-B is coming in
2020 (although I thought there was a "glider" exemption), but with
that being said, would it make any sense for FLARM units to be
required for gliders competing in any of our nationals (or maybe even
in regionals)?

As you are aware, we've had several mid-airs between gliders in recent
years and perhaps if gliders had been equipped with FLARM units in a
nationals or in a regionals, some of these mid-airs might have been
prevented.....Just a thought!

Thanks - Renny

Why not require ADS-B units instead. *Then you'd get the advantages of
FLARM, but you'd also see all of the transponder equipped GA aircraft
(assuming that there was a ground station in the area).

Now that Navworx is shipping their unit, this could happen tomorrow.
I'm sure that someone could talk Navworx into working with the major
glide computer manufacturers to provide the necessary interfaces if they
knew that this would be worth their while.

--
Mike Schumann

Mike

You are back again proposing the same NavWorx ADS-B transceiver for
glider cockpits that was discussed recently and just does not look
practical for our needs. While I'd love to see products that do meet
our needs, unfortunately there are currently no available UAT
transceivers that do appear suitable for use in gliders and none that
I am aware of that are coming in the near term that will change this.
Anybody able to share any different information?

So I'll repeat below again the issues with the NavWorx ADS600-B. Until
an ADS-B transceiver addresses these issues I don't see how it can
hope to have any wide adoption in glider cockpits.

---

1. The specified 0.8 Amp (scaled to @12V) power draw the Navworx
ADS600-B ADS-B transceiver is just too much to be interesting for most
glider cockpits. Do you have different information on the actual power
draw? This is the receiver box alone and today a display would need to
be added increasing this power consumption.

2. (A) The NavWorx does not support the FLARM serial display protocol
so is not compatible with most current PDA/PNA soaring software and
flight computers (e.g. the ClearNav) that all support the FLARM
display protocol. Navworx could implement this, and I've talked to
them about this, but it does not seem to be something they are
interested in doing now. With a current device with power consumption
that just does not fit what we need it would not seem to make business
sense for them to target delivering a glider specific display
protocol. It might make more sense combined with a future lower-power
consumption version of their devices. Given they are a small company
and just have their first transceiver going into the market I'd not
hold my breath. Their transceiver will likely be interesting for the
lower-end of the GA market who have older panels with Mode C
transponders and who do not have a Mode S transponder upgradable to
1090ES data-out, they really need TSO approval for the product to be
successful in the GA market and I kind of expect that is where their
resources are focused.

2 (B) The NavWorx and many other ADS-B receivers has no built-in
traffic warning or traffic filtering algorithms so won't itself warn
about traffic. It relies on the external display system to do this.
None of these systems available are tuned for gliders, i.e. provide
the type of threat detection and false alarm prevention required in
many glider situations, especially when thermalling in gaggles (likely
one of the contest scenarios worrying many people). And it is not just
a matter of working to connect the ADS-B box to existing gliding
software or flight computers. Those systems today support the Flarm
serial protocol - in this scheme the traffic threat processing is done
within the Flarm (or PowerFLARM) box, with a NavWorx receiver
connected that gliding software or flight computer will need to do the
threat assessment and false alarm prevention etc. itself. Having said
that I believe some of these soaring software and flight computer
vendors should be working to support basic display of ADS-B traffic
(and FIS-B weather etc.) -- this may make sense for example where ADS-
B is being used as an adjunct to a transponder in busy GA traffic
areas. I've actively tried to encourage some of those ADS-B and
soaring products vendors to play together for this reason. However I'm
just not sure those vendors would want to step up and do the FLARM
style traffic threat detection. Especially since most of their market
that cares about traffic warning is already using Flarm.

2 (C) The Flarm serial display protocol combines aircraft GPS location
and traffic data into a single serial stream so that one serial port
on a PDA or flight computer can receive both data. Other popular
display protocol used for ADS-B traffic display like the Garmin TIS
protocol does not do this and would require a separate serial port for
GPS position data and for traffic data or some external third party
hardware box to combine two serial ports. This won't be an issue for
everybody but I suspect will be a problem for a significant number of
pilots. Just adding support in the PDA or flight computer software for
one of these other display protocols does not change this problem. You
really need the ADS-B receiver product to support the Flarm serial
display protocol for the product to be easily usable in a wide range
of glider cockpits.

3. Cost. At US$2,495 list the NavWorx ADS600-B ADS-B transceiver is
significantly more expensive than a PowerFlarm (~$US1,695 list) by
itself (for it's Flarm to Flarm capability). When you factor in costs
of a display for the ADS-B and other components it is in the ball park
of say a PowerFLARM + Trig TT21 which can do ADS-B data-out. The TT-21
with 1090ES data or out or a similar 1090ES transponder, or even a UAT
transmitter, is required to have the PowerFLARM ADS-B receiver work
properly in the USA. (And technically unless you want to add a
currently expensive GPS receiver the TT21 cannot meet the 2020
mandatory ADS-B data-out requirements, but neither will the currently
non-TSO ADS600-B, but lucky we don't need to meet those requirements
for gliders). I think current ADS-B prices for an actual working
system of around $3k and more price it out of most glider cockpits
even if it actually did what was needed to help with the glider-on-
glider threat. While prices may fall over time I'd not hold my breath
for a radical reduction, I suspect current vendors are meeting early
adopter needs in the GA market and there won't be a lot of movement on
pricing until we get closer to 2020.

---

The Mitre UAT transceiver prototype while it should have low power
consumption compared to the Navworx ADS600-B it is just a prototype
and AFAIK has the other problems described above. I am happy seeing an
R&D platform and prototype device being developed and hopefully used
to work on issues relevant to ADS-B in gliders but it is a long way
from that to something Mitre or others can convince a manufacture to
want to make (effectively for the USA gliding community only, yikes
that's a small market) and then to something we can buy. And I'm not
really sure Mitre or anybody else are addressing the needs or the
glider cockpit. If they were the prototype would already have things
like serial FLARM support and threat assessment etc. handled on-board.
That is just such an obvious requirement for the gilder market.

Darryl