Ads-b and sailplanes

On Thursday, May 7, 2015 at 12:32:11 AM UTC-4, Andy Blackburn wrote:
On Tuesday, May 5, 2015 at 10:19:59 PM UTC-7, Mike Schumann wrote:

If you want a fully functional ADS-B IN / OUT system for under $1,000 you'll probably have to wait until this fall. These systems are going to use iPAD or iPHONE apps to provide the user interface. (I'm not counting the cost of iPhone / iPAD in the price of the system, as most people have these devices anyway).

If I'm flying a glider and I want to invest in avionics for anti-collision I wouldn't invest in anything that doesn't sent/receive Flarm protocol if I'm worried about gliders since the odds a glider is going to have anything other than Flarm is low. If I'm worried about fast jets I wouldn't invest in anything that doesn't light up both TCAS and SSR because they are faster it is much better for them to see me. That requires a transponder. Those considerations make anything UAT-only mostly useless as it depends on ADS-R to get even half of the job done. For GA I remain skeptical that UAT will outsell 1090ES, even in GA.

9B

The question is, do you want to end up with an avionics package that doesn't see UAT ADS-B OUT equipped traffic? It's hard to predict how much of the GA or UAV fleet will go down that road, but it could be a pretty significant percentage if there is a significant price difference between UAT and 1090ES ADS-B OUT solutions.

That's not to say that FLARM isn't a good solution for glider pilots that are flying in competitions. FLARM is specifically designed for collision avoidance for aircraft that are flying at close quarters. ADS-B is designed to give people a heads up so they can stay far away from any conflicting traffic before it becomes a threat. It's really unfortunate that the PowerFLARM folks only solved part of the problem rather than come up with a comprehensive solution that takes into account the UAT / 1090ES architecture of the US ADS-B system.

In Europe I don't think this is even a discussion. The risk to gliders is nearly all glider to glider. Some GA owners are installing PF also.

At 07:21 07 May 2015, waremark wrote:
In Europe I don't think this is even a discussion. The risk to gliders is
nearly all glider to glider. Some GA owners are installing PF also.

Not just GA! The Vulcan bomber is installing PF this spring and the RAF
BBMF
have installed it in all their aircraft.

On Thursday, May 7, 2015 at 3:15:06 PM UTC-4, Benedict Smith wrote:
The Vulcan bomber is installing PF this spring and the RAF
BBMF
have installed it in all their aircraft.

Is this to avoid transponder-less gliders or are they installing PF to avoid collision with other bombers in close formation flying? I wonder what sorts of testing they did.

At 01:26 08 May 2015, son_of_flubber wrote:
On Thursday, May 7, 2015 at 3:15:06 PM UTC-4, Benedict Smith wrote:
The Vulcan bomber is installing PF this spring and the RAF
BBMF
have installed it in all their aircraft.

Is this to avoid transponder-less gliders or are they installing PF to
avoid collision with other bombers in close formation flying? I wonder
what sorts of testing they did.

Nothing quite so exciting, both the Vulcan and the BBMF planes fly in air
show displays, this is mostly to provide increased public tracking and also

because of the number of smaller aircraft associated with air shows.
The RAF have been quite encouraging in their support for public tracking of

their display flights.

On Thursday, May 7, 2015 at 1:08:27 AM UTC-5, Mike Schumann wrote:

The question is, do you want to end up with an avionics package that doesn't see UAT ADS-B OUT equipped traffic? It's hard to predict how much of the GA or UAV fleet will go down that road, but it could be a pretty significant percentage if there is a significant price difference between UAT and 1090ES ADS-B OUT solutions.

The problem is, in order to see ALL ADS-B traffic, you HAVE to have ADS-B out. So to get reliable info, you have to have, at a minimum, about $1500 for a Skyguard UAT transceiver and and $500 for an iFly display to show the data. Or an iPhone 6+, same price.

And how many gliders are going to do that? Most racers won't - they'll stick to PF for the collision warning advantage (and leeching benefits). Out west, they will most likely go with 1090ES out to trigger jet TCAS, and PF to see other gliders.

Just getting an ADS-B receiver is fine for weather and NOTAMS, but a really flawed solution for traffic - much worse than PF, for all the reasons that have been discussed ad nauseum in this thread.


That's not to say that FLARM isn't a good solution for glider pilots that are flying in competitions. FLARM is specifically designed for collision avoidance for aircraft that are flying at close quarters. ADS-B is designed to give people a heads up so they can stay far away from any conflicting traffic before it becomes a threat. It's really unfortunate that the PowerFLARM folks only solved part of the problem rather than come up with a comprehensive solution that takes into account the UAT / 1090ES architecture of the US ADS-B system.

Mike, has it occurred to you that since the US is the only country to use UAT, there isn't a big enough market for it at present? But in Europe, the PF makes total sense, since it will display ALL ADS-B (1090ES) traffic AND gliders?

Kirk
66

On Thursday, May 7, 2015 at 7:40:59 AM UTC-7, kirk.stant wrote:
The problem is, in order to see ALL ADS-B traffic, you HAVE to have ADS-B out. So to get reliable info, you have to have, at a minimum, about $1500 for a Skyguard UAT transceiver and and $500 for an iFly display to show the data. Or an iPhone 6+, same price.

Uh no, to see all ADS-B traffic you just need to have receivers for both UAT and 1090ES, both transmit continuously whether or not there is other ADS-B traffic in the area. It is ADS-R from ground stations that may not be transmitted if there are no detected ADS-B out targets in the area.

On Thursday, May 7, 2015 at 12:20:41 PM UTC-5, wrote:

Uh no, to see all ADS-B traffic you just need to have receivers for both UAT and 1090ES, both transmit continuously whether or not there is other ADS-B traffic in the area. It is ADS-R from ground stations that may not be transmitted if there are no detected ADS-B out targets in the area.

Are you sure? As I understand it, unless you transmit ADS-B out, you will not get all the UAT ADS-B out traffic. You will only see them when a UAT ADS-B out is getting traffic info for all the traffic near him. And you have to be in range of a ground station.

Agree that with a 1090ES receiver (such as a PF), you will see all 1090ES traffic nearby - but not UAT-only ADS-B traffic.

Kirk
66

On Thursday, May 7, 2015 at 2:14:58 PM UTC-7, kirk.stant wrote:
Are you sure? As I understand it, unless you transmit ADS-B out, you will not get all the UAT ADS-B out traffic. You will only see them when a UAT ADS-B out is getting traffic info for all the traffic near him. And you have to be in range of a ground station.

1090ES and UAT ADS-B out devices continuously transmit position and velocity vector once or twice per second (I'm hazy on which it is). A ground station may suppress transmission of TIS-B and ADS-R, if there is no ADS-B target of the corresponding type in the coverage area.

Marc

On Wednesday, May 6, 2015 at 11:08:27 PM UTC-7, Mike Schumann wrote:

The question is, do you want to end up with an avionics package that doesn't see UAT ADS-B OUT equipped traffic? It's hard to predict how much of the GA or UAV fleet will go down that road, but it could be a pretty significant percentage if there is a significant price difference between UAT and 1090ES ADS-B OUT solutions.

That's not really the right question. The question is how do you trade off total cost versus the probability of potential collision scenarios.

If you can only afford a single device for most glider pilots the right choice is a PowerFlarm, which will get you anticollision for other PF-equipped gliders, plus PCAS for all transponder-equipped aircraft being painted by SSR or TCAS, plus 1090ES In for most (and in 2020 ALL) aircraft that fly in Class A.

Under some less common circumstances your best choice if you can afford only once device is to buy a transponder (preferably Mode S). This will make you visible to most high-performance aircraft equipped with TCAS AND to SSR AND to GA with PCAS. Modern Mode S transponders also have an upgrade path to 1090ES Out which will make you visible to most ADS-B equipped aircraft either directly or via ADS-R. Keep in mind that it is generally better for the higher performance aircraft to detect the lower performance aircraft rather than the other way around as they have more degrees of freedom.

If you can afford two devices you are best off installing a PowerFlarm AND a transponder. This will allow you to see and/or be seen by all transponder, PowerFlarm and 1090ES Out aircraft and will allow you to upgrade to 1090ES Out which will also make you visible to aircraft carrying UAT In/Out but aren't carrying a transponder or talking to ATC - not sure how many of these there will be given the regulations overlap between ADS-B and transponders.

If you want to install three devices you can consider UAT-In - this will additionally give you coverage of aircraft that are not carrying a transponder but are carrying UAT Out. It will also allow you better granularity in seeing UAT-Out aircraft and any UAVs that are flying outside MOAs or wander above the 400' FAA limit ASSUMING they are equipped with UAT instead of 1090ES - not clear that UAVs are going to be a big deal or that UAT would be preferred to 1090ES for them. Based on the statistics, this does not seem like a good return on investment in terms of risk reduction. I am personally skeptical that many GA aircraft will equip with UAT Out over 1090ES Out and am particularly skeptical that they will eschew transponder carriage so you wouldn't see them on PowerFlarm's PCAS.

The idea of picking UAT In before PowerFlarm and/or a Mode S transponder defies all the traffic, equipment and collision statistics. If you want it as a third device knock yourself out, but it is definitely well past the point of diminishing returns.

9B