Notable Power Flarm saves - Is it 'worth it'?

On Wednesday, May 2, 2018 at 11:39:37 PM UTC-4, Darryl Ramm wrote:
^ BTW PowerFLARM (with the ADS-B option) also includes a PCAS capability

Darryl, can you explain that further, for those of us who are dazed and stupefied when confronted with the FAA's alphabet soup? AFAIK, PF does not transmit anything that the ATC system receives, so how can it give you collision warnings for non-FLARM aircraft, other than the warning about the presence of a transmitting transponder nearby?

Also, you say a cheap used mode C transponder is a good addition to a glider. Can you explain further what that will get you? E.g., will ATC still see you after 2020? Will PowerFLARM devices sense your mode C transponder transmissions? Will the collision-avoidance equipment on airliners detect you, now and in the future?

On Thursday, May 3, 2018 at 7:42:20 AM UTC-7, wrote:
On Wednesday, May 2, 2018 at 11:39:37 PM UTC-4, Darryl Ramm wrote:
^ BTW PowerFLARM (with the ADS-B option) also includes a PCAS capability

Darryl, can you explain that further, for those of us who are dazed and stupefied when confronted with the FAA's alphabet soup? AFAIK, PF does not transmit anything that the ATC system receives, so how can it give you collision warnings for non-FLARM aircraft, other than the warning about the presence of a transmitting transponder nearby?

That's all PowerFLARM does for transponder threats: PCAS. PowerFLARM does not transmit anything seen by ATC or non-FLARM/PowerFLARM equipped aircraft.

Almost all PowerFLARM in the USA have the "ADS-B" option which also includes PCAS capability. PCAS systems listens for transponders replying to other interrogators (SSR, TCAS, TCAD). It sees the altitude reported in those Mode C or S replies and guesses the distance from the received power. So accurate altitude, approximate distance and no directional information.

Also, you say a cheap used mode C transponder is a good addition to a glider. Can you explain further what that will get you? E.g.,
will ATC still see you after 2020?

Yes. There is nothing happening in 2020 that affects this, including the ADS-B Out carriage mandate becoming effective.

Will PowerFLARM devices sense your mode C transponder transmissions?

Yes. As long as your Transponder is being interrogated by SSR (aka ATC radar), TCAS or TCAD (lower-cost TCAS like systems). But only PowerFLARM with the ADS-B option, which almost all in the USA have, ...*don't* buy PowerFLARM "Pure" in the USA. There are settings in the PowerFLARM that can disable PCAS or adjust the filtering of PCAS targets.

Will the collision-avoidance equipment on airliners detect you, now and in the future?

Yes. That's one of the big reasons for getting a transponder, Mode C or Mode S. In fact TCAS requires a transponder in the threat aircraft, if your aircraft happens to have UAT Out and no transponder... TCAS II will let an airliner fly right into your glider with no collision RA (which is the main reasons that UAT Out in gliders was always a bad idea).

There is no plan to end of life Mode C in the USA, there was some talk from the FAA on long term reducing the number of approach radar systems (which would impact Mode S transponder without ADS-B Out equally). None of that seems to be even planned yet. There already issues with ADS-B Out equipage being behind schedule, and removing some approach radar systems has other issues, including possible national security ones.

One downside of Mode C transponders near other gliders is that the Mode C transponder replies unlike Mode S replies do not contain an ICAO number and its harder for the PowerFLARM to guess say that a PowerFLARM and Mode C equipped glider are the same target. But this is also going to happen at times when Mode S transponders get interrogated by a old Mode C interrogator, like most of the TCAD systems flying around... then the Mode S transponder has to emulate a Mode C transponder.

My message for a long time has been: If you fly near areas of dense airliners, fast jets and military traffic, just get a transponder, Mode S or used Mode C does not matter... get what you can afford.

Mode S, at least with a Trig transponder, has the additional benefit of being able to do ADS-B Out. Not all Mode S transponders can do ADS-B out or TABS. The Trig TT22 is currently *the* Mode S transponder to purchase for ADS-B Out in gliders in that USA.

My message for a long time has been: If you fly near areas of dense airliners, fast jets and military traffic, just get a transponder, Mode S or used Mode C does not matter... get what you can afford.


This seems logical, but I heard another corner case where might not be so.

I sat in a presentation from our local Approach Control folks. They noted that with the new ADSB ground stations they had better visibility than from their existing radar plus ModeC. Specifically, low and far out. This like it might permit them to route controlled traffic in new places where gliders are, but where a Mode C transponder on the glider might not help.

On Sunday, May 6, 2018 at 6:25:25 AM UTC-7, wrote:
My message for a long time has been: If you fly near areas of dense airliners, fast jets and military traffic, just get a transponder, Mode S or used Mode C does not matter... get what you can afford.


This seems logical, but I heard another corner case where might not be so..

I sat in a presentation from our local Approach Control folks. They noted that with the new ADSB ground stations they had better visibility than from their existing radar plus ModeC. Specifically, low and far out. This like it might permit them to route controlled traffic in new places where gliders are, but where a Mode C transponder on the glider might not help.

You need to do a bit more thinking about the flaws in your logic here.

A transponder provides visibility to TCAS and IFF systems in airliners, fast jets and (some) military traffic...

If ATC was about to do this, and direct traffic towards areas where gliders are it is more reason to want to have a transponder.

If in this scenario you also wanted ADS-B out, then a Mode S transponder is the way to go. I hope you spoke up and talked about gliders in the area and what they are or are not equipped with. I'd have possibly also pointed out the Chicago 737-glider NMAC last year as an example....

On Sunday, May 6, 2018 at 6:25:25 AM UTC-7, wrote:
My message for a long time has been: If you fly near areas of dense airliners, fast jets and military traffic, just get a transponder, Mode S or used Mode C does not matter... get what you can afford.


This seems logical, but I heard another corner case where might not be so..

I sat in a presentation from our local Approach Control folks. They noted that with the new ADSB ground stations they had better visibility than from their existing radar plus ModeC. Specifically, low and far out. This like it might permit them to route controlled traffic in new places where gliders are, but where a Mode C transponder on the glider might not help.

Unfortunately, what the Approach Control folks failed to mention that their software removes targets of anything less than 70 mph ground speed. This is to remove the clutter from highway traffic. It also removes most gliders unless we have electronic identification measures. YMMV with each approach personnel. PDX was pretty clueless about gliders and their senior controller didn't know what the 1202 transponder frequency identified. They have since programed 1202 to print "glider" on their screen.
Craig

On Sunday, 6 May 2018 09:12:34 UTC-6, Craig Reinholt wrote:
On Sunday, May 6, 2018 at 6:25:25 AM UTC-7, wrote:
My message for a long time has been: If you fly near areas of dense airliners, fast jets and military traffic, just get a transponder, Mode S or used Mode C does not matter... get what you can afford.


This seems logical, but I heard another corner case where might not be so.

I sat in a presentation from our local Approach Control folks. They noted that with the new ADSB ground stations they had better visibility than from their existing radar plus ModeC. Specifically, low and far out. This like it might permit them to route controlled traffic in new places where gliders are, but where a Mode C transponder on the glider might not help.

Unfortunately, what the Approach Control folks failed to mention that their software removes targets of anything less than 70 mph ground speed. This is to remove the clutter from highway traffic. It also removes most gliders unless we have electronic identification measures. YMMV with each approach personnel. PDX was pretty clueless about gliders and their senior controller didn't know what the 1202 transponder frequency identified. They have since programed 1202 to print "glider" on their screen.
Craig

Salt Lake City Approach and Center has implemented the same, GLDR appears on the screen when a 1202 squawk code is received.

The Utah Soaring Association has a great relationship with SLC ATC and Center for general glider flying and during events at Nephi and Logan. I highly recommend you contact the ATC and sit down with, explain where and when you fly and educate them. They want to be informed and eliminate surprises.

Ron Gleason

On Sunday, May 6, 2018 at 8:12:34 AM UTC-7, Craig Reinholt wrote:
On Sunday, May 6, 2018 at 6:25:25 AM UTC-7, wrote:
My message for a long time has been: If you fly near areas of dense airliners, fast jets and military traffic, just get a transponder, Mode S or used Mode C does not matter... get what you can afford.


This seems logical, but I heard another corner case where might not be so.

I sat in a presentation from our local Approach Control folks. They noted that with the new ADSB ground stations they had better visibility than from their existing radar plus ModeC. Specifically, low and far out. This like it might permit them to route controlled traffic in new places where gliders are, but where a Mode C transponder on the glider might not help.

Unfortunately, what the Approach Control folks failed to mention that their software removes targets of anything less than 70 mph ground speed. This is to remove the clutter from highway traffic. It also removes most gliders unless we have electronic identification measures. YMMV with each approach personnel. PDX was pretty clueless about gliders and their senior controller didn't know what the 1202 transponder frequency identified. They have since programed 1202 to print "glider" on their screen.
Craig

And to be very clear on what Craig is saying, he is talking about primary radar doppler discriminators filtering slow moving aircraft so they are not seen on ATC primary radar, this is *not* SSR (Secondary Surveillance Radar) that detects transponders. If your glider has a transponder it will be seen by ATC via SSR any time it is within SSR coverage, independent of airspeed.

I have to say this because I know there is still confusion out there, including hearing people get this completely backwards and claim that this filtering is an issue with transponders, it's not... its a reason why you want a transponder.

On Sunday, May 6, 2018 at 8:42:20 AM UTC-7, Darryl Ramm wrote:
On Sunday, May 6, 2018 at 8:12:34 AM UTC-7, Craig Reinholt wrote:
On Sunday, May 6, 2018 at 6:25:25 AM UTC-7, wrote:
My message for a long time has been: If you fly near areas of dense airliners, fast jets and military traffic, just get a transponder, Mode S or used Mode C does not matter... get what you can afford.


This seems logical, but I heard another corner case where might not be so.

I sat in a presentation from our local Approach Control folks. They noted that with the new ADSB ground stations they had better visibility than from their existing radar plus ModeC. Specifically, low and far out. This like it might permit them to route controlled traffic in new places where gliders are, but where a Mode C transponder on the glider might not help.

Unfortunately, what the Approach Control folks failed to mention that their software removes targets of anything less than 70 mph ground speed. This is to remove the clutter from highway traffic. It also removes most gliders unless we have electronic identification measures. YMMV with each approach personnel. PDX was pretty clueless about gliders and their senior controller didn't know what the 1202 transponder frequency identified. They have since programed 1202 to print "glider" on their screen.
Craig

And to be very clear on what Craig is saying, he is talking about primary radar doppler discriminators filtering slow moving aircraft so they are not seen on ATC primary radar, this is *not* SSR (Secondary Surveillance Radar) that detects transponders. If your glider has a transponder it will be seen by ATC via SSR any time it is within SSR coverage, independent of airspeed.

I have to say this because I know there is still confusion out there, including hearing people get this completely backwards and claim that this filtering is an issue with transponders, it's not... its a reason why you want a transponder.

Aaak! Sorry for not being clear on my post. What Darryl said!