Gliders and Transponders......again.

On Jan 22, 11:35*am, wrote:
On Jan 19, 4:24*pm, Martin Gregorie



wrote:
On Mon, 19 Jan 2009 10:06:40 -0800, Darryl Ramm wrote:
I know nothing about UK airspace (besides being stuck in it for far too
much time as a passenger holding over Heathrow), but it sounds like the
existing separation of airliner and jets in UK airspace is a key point
you folks should be arguing.

Yes, agreed. The public will be with us on noise grounds if the commuter
airlines get their way and start flying direct routes through class G
airspace - this is something they can't do at present, but the CAA's
transponder consultation seems designed to let them do it.

And again only one of the transponder aircraft needs to be talking to
ATC/radar facilities or have PCAS or higher. *I don't know PCAS (and
higher-end systems) adoption in low-end GA aircraft in the UK, but in
the USA it seems pretty high (purely an anecdotal impression). I've
asked before but could not get adoption numbers for the USA.

I've not seen figures either, but the GA density is probably lower here..
There are flying schools on either side of our club field and there's no
doubt that our weekend movements vastly outnumber both of theirs.

In the Libelle you might be able to make up a mount for a Zaon MRX under
the opaque areas of the front of the canopy.

There's less space there than you might imagine. The panel is inset no
more than 65mm (2.5"), so an end-on cigarette pack would not fit under in
font of the panel while anything thicker would start to hide the top row
instruments.

It might be canted over parallel to the surface,

It would have to be. If it was in the center it would interfere with the
canopy lock. On the other hand, the antenna is probably not an issue - a
remote one could be mounted above the instrument tray that forms the
front of the panel. My GPS antenna is mounted there and gets an excellent
view of the sky.

I wouldn't want anything much bigger than a MH flowmeter on the cockpit
wall in front of me: lets just say the cockpit is 'snug'.

--
martin@ * | Martin Gregorie
gregorie. | Essex, UK
org * * * |

The proponents of transponders in gliders should study a recent
Transportation Safety Board of Canada investigation report into a
tragic mid-air collision between a Cessna 182 and a Cessa near Toronto
in August 2006. Three people died in the collision. The full
investigation report is available on the TSB web site athttp://www.tsb.gc..ca/eng/rapports-reports/aviation/2006/a06o0206/a06o...

The TSB report states: "Both aeroplanes were operating in accordance
with visual flight rules in Class E airspace....Both aeroplanes were
equipped with functioning transponders. C-GCHN was also equipped with
a traffic information service (TIS) system that can provide a display
of nearby aircraft using information provided by ground-based radar;
this service is not available in Canada."

A transponder can reduce the risk of collision with Traffic Collision
Advisory System (TCAS) equipped aircraft, i.e. mostly air transport
category aircraft. Maybe that reduction in risk is worth the cost in
some places.

However, as this accident shows, simply installing a transponder gives
no guarantee against collision with non-TCAS equipped aircraft.

Ian Grant
Ottawa Canada

"simply installing a transponder gives no guarantee against collision
with non-TCAS equipped aircraft."

We'll I don't recall anybody claiming that there are any collision
avoidance guarantees anywhere. And how transponders *can* help reduce
collision risks with non-TCAS etc. equipped traffic has been discussed
in this thread already.

So let's go over this again. Can a transponder help with traffic
avoidance even if the involved aircraft don't have TCAS -- very
clearly yes -- A transponder equipped aircraft under control (or in
communications with) a radar facility can be provided avoidance
information or traffic information by that facility. Those of us who
fly in high traffic areas see and hear these ttaffic advisories all
the time. In addtion there are alternatives to TCAS available,
starting with Zaon MRX type PCAS systems, up through the active
interrogation Avidyne and other systems, right through to full on
TCAS. Since it seems neither aircraft in this fatal crash were in
touch with a radar facility, maybe lives could have been saved by one
of the aircraft having a $500 Zaon MRX. I assume the families of the
three people killed would have wished that at least one person had at
least believed enough in PCAS technology to be using one. At some
point somebody had spent $10k or so to have TIS in one aircraft, even
it it was not supported by any SSR facility near where they were
flying. There are no guarentees in life, or death, and who knows for
sure if the PCAS would have avoided this accident but at an amortized
cost per death of $170 or so in hindsight is seems a tragically cheap
insurance.

Now back to where this thread started, I think the concern from the op-
ed piece seemed to be more focused on private jets and airliners but
it lost the thread along the way. Maybe I'm projecting too much on
that, because that, and the damage that a collision with large numbr
of fatalities would do to soaring, is where my concern is. That
traffic, with high percentage of TCAS installations, especially in the
large iron, is going to be well warned of transponder equipped
gliders. And those fast moving TCAS-II equipped jets are much better
handled to avoid a transponder equipped glider than the glider is to
avoid them. So while I'm happy to keep correcting incorrect claims
like the "need TCAS" above I really don't care about the risk to
individual glider pilots in mid-air collisions. It's your choice to
install a PCAS or not, but if you fly in or near high-traffic areas
with airlines/jets please help reduce the risk of a disaster and
install and use a transponder.

BTW the Canadian report does go over soem goo issues with "see and
avoid". But it is a little bizarre as it widely mentions things like
ADS-B, glider transponder exemptions and even FLARM but does not
mention PCAS or similar systems.

Darryl