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FAA Amends ADS-B For LSA


gbigs

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That is really great news. A lot of credit has to go to the EAA and AOPA for their efforts, along with us that wrote in for a decision that would make sense.

Now, to get Garmin to give us a software upgrade to let the 796 talk to the GTX 330  ES? Why not, It's WAAS capable and will send reliable position reports to the ATC ground stations for a return of the complete traffic picture.

 

Or may be a good avionics shop can make it workable?

 

Here's hoping!

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Sorry, Rich, your local avionics shop wont be able to help.  The ADS-B datastream requires more than the position and the 796 does not provide it.  Garmin could do this within the 796, though, but stated to me (via support and Team X) that this was not in the product roadmap.  Here's to hoping!

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Hi Dave,

 

I spoke to Garmin last year about this very thing. At that time their answer was, "it's a portable and will never be allowed by the FAA. It just is not going to happen."

 

Well, now it looks like it may be possible. I'm going to call Garmin and make my views known again. Also, I'm going to write EAA and AOPA about this once more.

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Rich -- hope you have better luck with Garmin than me

 

 

Most recent description of the problem:

Thank you for contacting Garmin:

 

There are no plans to enable or allow the AERA 795 as a WAAS GPS position source for ADS-B out devices to include experimental applications.   

 

Thank you and best regards,

  

Aaron S.

  

Aviation Field Support Specialist

 

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Dynon posted about this on VAF Forums.  Below is a quote from a Dynon rep:

 

 

"To Dynon, it's a clarification of what was always the way we operated. The old language was:


Quote:
meets the requirements of TSO-C166b; or TSO-C154c

New language:



Quote:
meets the performance requirements of TSO-C166b; or TSO-C154c

It's pretty easy to read in the first one that you didn't need to actually get the TSO, you just needed to meet it. It's nice they made this even more clear, but Dynon has not been holding out for this change to sell something.

The TSO for ADS-B and the GPS is extremely complex. In this case, the TSO paperwork is not the issue. It's the design the TSO requires and the tests you need to run in order to show you meet the TSO. Once you do all that work, why not file for the TSO? 

Hence the reason Dynon sells a fully TSO'd transponder with ADS-B Out. There's no particular savings if you need to demonstrate compliance with so many technical details.

Statically testing a GPS on the ramp does not prove it is TSO'd. One of the difficult things a device that meets the TSO needs to do is provide an accurate solution even when satellites are mis-behaving (and prove you do so). There's no affordable way for a shop to to test this on the ground, and your non-TSO'd GPS will fail it anyway. Then you need a "System Design Assurance" of 1x10-5, which you can't demonstrate with a simple single test, you have to know how the system (read: software) was designed, documented, coded, complied, etc.

So unfortunately, while this at least shows the FAA is open to making the rules easier to interpret, it doesn't open up any new routes for experimental aircraft to install less expensive equipment. Dynon will keep working hard to see if we can get some other changes through to provide more solutions for experimentals.

--Ian Jordan
Dynon Avionics"

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Sorry, Rich, your local avionics shop wont be able to help.  The ADS-B datastream requires more than the position and the 796 does not provide it.  Garmin could do this within the 796, though, but stated to me (via support and Team X) that this was not in the product roadmap.  Here's to hoping!

 

The 796 works perfectly as WAAS/GPS input for the Dynon Skyviews and the SV-ADSB-470 UAT Band Traffic and Weather Receiver.

.....I have had ADS-B in/out operating in the CTLSi for over a year.    I also have the Skyvew SV-XPNDR-26X Mode-S xpndr.

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The 796 works perfectly as WAAS/GPS input for the Dynon Skyviews and the SV-ADSB-470 UAT Band Traffic and Weather Receiver.

.....I have had ADS-B in/out operating in the CTLSi for over a year.    I also have the Skyvew SV-XPNDR-26X Mode-S xpndr.

 

Are you sure the 796 is being used as your ADS-B position source, and not the internal GPS receiver in the Skyview unit?

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Are you sure the 796 is being used as your ADS-B position source, and not the internal GPS receiver in the Skyview unit?

 

This really is a confusing topic. I find it fascinating that (not all, I realize) some of our FD and other S/E-LSA aircraft are equipped with such amazing flight planning/awareness technology and safety systems. As a pilot who never flew before GPS or even Loran systems I struggle to imagine the stress/workload due to basic navigation -- something many of us take for granted today. Anyway... 

 

If you have an ADS-B OUT equipped system using a non-certified GPS Source (Garmin Portable, SkyView, etc.) try e-mailing your N# to 9-AWA-AFS-300-ADSB-AvionicsCheck@faa.gov. You'll get a very nice PDF Attachment that basically says, "Oh, hi. Yes, we see you sending data but the integrity level is non-compliant." Technically it's more like this:

 

SDA & SIL = zero indicates a system using a non-compliant GPS but adheres to the guidance contained in AC 20-165A. You should still be able to receive traffic and weather services, but will need a compliant GPS to qualify for ATC services in ADS-B only airspace prior to the mandate and to operate in §91.225 airspace after the 2020 mandate.  

 

Then we have to consider this from the SkyView Pilots User Guide:

 

ADS-B OUT Transmissions

ADS-B OUT transmissions that meet the 2020 FAA ADS-B equipment mandate require that a TSO 146c GPS signal be directly provided from the GPS to a capable ADS-B device (such as the SV-XPNDR-26X). [...snip for brevity...] This means that currently, the SV-XPNDR-26X’s ADS-B transmissions are not at a high enough integrity level to meet the FAA’s 2020 ADS-B equipment mandate.

 

Ok now what? Good question. Steve from Dynon Tech Support was kind enough recently to offer this explanation which I thought made a lot of sense:

 

The ADS-B system makes NOTE that your plane's SIL is 0 (as the report indicates), but it doesn't DO anything about it. Likely after 2020, if you have a SIL Level of 0, that will cause a non-compliance report to be automatically generated (you won't have to ask... :-).

 

As we understand it, the FAA's not currently "throwing away the data" just because the SIL is 0.

 

Again, as we understand it, the FAA has no issue about ADS-B OUT data having SIL 0 - it CAN'T, because its rules state that you're not REQUIRED to have a system that's compliant with the FAA 2020 ADS-B mandate UNTIL 2020. So, again, as we understand it, the FAA is pretty happy to have pilots on the ADS-B system with ADS-B OUT and ADS-B IN - even if you have SIL 0. (The FAA has [quietly] been surprised at the high[er] level of experimental planes equipped with ADS-B OUT and ADS-B IN... largely driven by Dynon's reasonable prices for adding ADS-B OUT and ADS-B IN to an existing SkyView system.)

 

Dynon's perspective is that the biggest advantage to being equipped with ADS-B OUT is that a plane that equipped with ADS-B OUT can then request the ADS-B ground station(s) to transmit a customized ADS-B (IN) TRAFFIC (picture? portrait? situation?). For this to happen, the ADS-B system needs to know where that plane actually IS (ADS-B OUT). Some companies feel differently, that it's adequate to just have an ADS-B IN unit that picks up incidental ADS-B traffic broadcasts intended for other planes. Dynon feels that your SkyView system should only show ADS-B traffic that is specific for your plane - not incidental broadcasts that may not be relevant or complete.

 

And, I think to tie all of these threads together, the ADS-B system doesn't currently "care" about whether you have a certified GPS directly connected your Mode-S transponder such as is currently the case with a SkyView system with a (UNcertified) SV-GPS-250 as its only GPS receiver. The ADS-B replies for your plane are being sent to your plane (your ADS-B IN / SV-ADSB-470) regardless of whether you have a certified GPS connected to your Mode-S transponder.

 

Clear as mud, right?  :blink:  Based on Dynon's response (Post #10 above) to the information outlined in the article posted by the OP, I'm not so sure much has really changed. Maybe just maybe the FAA will find a way for a non-certified GPS sources like the Dynon unit to comply with ADS-B OUT standard. I'm not holding my breath.

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It would be nice if the FAA used the SIL bit and transmitted it to other aircraft instead of just looking at it.  For example, you could setup a system where VFR aircraft are not required to have TSO-compliant hardware, but instead just "conforming hardware" using a WAAS GPS source and ADS-B transceivers (UAT or 1090ES).  The SIL bit could be noted and passed along to all traffic.

 

That way, you could have IFR traffic required to use "true blue" TSO gear to make sure everything is as accurate and reliable as possible, and VFR traffic would have similar accuracy and reliability 99.5% of the time, but not completely assured.  Because the SIL bit is transmitted, all traffic knows what the confidence is in the position information of all other traffic.  Displays could mark non-TSO aircraft by color to indicate their position data may not be 100% accurate but close enough for VFR separation.

 

You could get traffic calls like "traffic, ten o'clock, three miles, same altitude, non-compliant".  This tells the pilot where the traffic almost certainly is, but to maybe look around a bit because this is an aircraft using non-TSO hardware and could have position errors.  99.5% of the time it won't, but it *might*.  If you want to get draconian, make ADS-B position checks coincide with transponder biannual checks, to ensure nobody's ADS-B setup gets crazy out of whack for very long.

 

Ta-da.  We now have precise position data for everybody, and TSO hardware in place for the aircraft where we really can't afford to be wrong about position by even a little (IFR).  And pilots who are strictly VFR have far better position data than the old radar system, without bankrupting them.  Plus ATC can tell at a glance whether an airplane should be allowed to file an IFR flight plan by just referencing the SIL bit.

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Are you sure the 796 is being used as your ADS-B position source, and not the internal GPS receiver in the Skyview unit?

 

The input GPS source is configured in the settings for the Skyviews.  I have also had the Dynon autopilot flying flight plans loaded into the 796.

 

Recall after describing the setup that my aircraft would be compliant for the 2020 mandate.   I predicted the FAA would not make the LSA or experimental world put in TSO'd gear for this...and now it's reality.

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Our local FSDO rep gave a presentation on ADS-B to our EAA chapter. He said the only place it will be required will be A, B & C airspace. As a Sport Pilot I am not allowed to fly in A (except over the mountains), I have no desire to fly into class B (although the trip around may get longer without ADS-B ), and class C is rare (at least in my part of the country).

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Our local FSDO rep gave a presentation on ADS-B to our EAA chapter. He said the only place it will be required will be A, B & C airspace. As a Sport Pilot I am not allowed to fly in A (except over the mountains), I have no desire to fly into class B (although the trip around may get longer without ADS-B ), and class C is rare (at least in my part of the country).

 

IIRC it's not just that, but also the "footprint" of those airspaces.  Meaning you cannot fly under a class B or C shelf, or over a class C airspace.  That is much more limiting.  My home airport is about 15 miles from the start of ATL class B, and there are lots of small airports only accessible by flying under a shelf.

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Our local FSDO rep gave a presentation on ADS-B to our EAA chapter. He said the only place it will be required will be A, B & C airspace. As a Sport Pilot I am not allowed to fly in A (except over the mountains), I have no desire to fly into class B (although the trip around may get longer without ADS-B ), and class C is rare (at least in my part of the country).

Except , if you are in the B and C "Veil" outside B and C airspace, you must have ADS-B out. That is my understanding.

 

Cheers

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Doug --  FSDO was wrong in their opinion for Class B.  Check the AC referenced above and the quote below.

 

 

(B) Except as provided for in § 91.225(e), within 30 nautical miles (NM) of an airport listed in part 91 appendix D (Mode C veil), section 1, from the surface upward to 10,000 feet mean sea level (MSL).

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