ADS-B and Flight Design

[MarkS]

I am assuming I'll need an LOA to install a Garmin GDL 88 or NavWorx ADS600BG box in a CTSW.  Does anyone have info on this? I thought I'd ask here before giving FD a call, since someone here may have already done an install.

[Anticept]

If you are S-LSA, you must have some sort of factory approved equipment list or LOA.

[FlyingMonkey]

I'd bet Dave Armando at FD has been asked a bunch of ADS-B compliance questions, and probably already has answers to most of them.

[MarkS]

Thanks for your comments.  My question pertains to S-LSA, and the LOA from FD is necessary.  I spoke with Dave at FD, who said that they will have solutions for 2020 compliance by the end of the year (as stated in posts, above).  He thought that getting an LOA for a GDL 88 install would be doable.  That's good news for those like me, who are not equipped with Skyview or a TSO'd gps.  I didn't ask him about the NavWorx box.  Given the above, I'll reconsider my options, including NavWorx, next year, when FD will be ready with their recommendations. 

[Kennith]

A recent blog by Mac McClellan adds one more layer of confusion to the ADS-B mandate.

 

URL: http://macsblog.com/2014/12/can-you-install-ads-b-now-maybe-not

 

Since ADS-B requires at a minimum a certified GPS plus either a Mode S-ES (the extended squitter feature that you can add to a Mode S, like the GTX-330, for about $1500), or a UAT, FD will have to issue an LOA for some specific models of certified GPS and UAT (since the GTX-330 installation is already specified in the MM), according to ASTM regulations.

 

But, the ASTM regulations don't satisfy what the FAA requires when it comes to LSA, or Experimental, in regard to ADS-B.

 

There is a great PDF from the AEA on how to install ADS-B:

 

URL: www.aea.net/Training/courses/ADSBForum/pdf/

 

PDF: ADS-B Installation Guidance.pdf

 

Note that their is no route for complying with ADS-B via ASTM LOA's, since an LOA is not an STC.

 

There do appear to be good reasons to opt for a UAT+GPS instead of Mode S-ES+GPS, since Mode S is not required below FL180, and the FAA wants to encourage the use of UAT due to frequency congestion in the US.   Since not many CT's are going to be flying international, and certainly none of them will be at FL180, it doesn't make much economic sense to go for Mode S-ES, unless its already installed.  It might not even make much sense even if a GTX-330 is already installed, as the upgrade cost to ES costs as much, if not more, than adding a UAT.

 

Even after FD finally chooses some UAT and GPS units for the CT LOA, we might still not be in compliance without some further changes by the FAA.

 

All of this has made me want to delay installing ADS-B equipment until there is some clarity from the FAA on how both LSA and Experimental will be able to comply.

[Anticept]

Hi Kennith!

Reading that blog just smacks of agenda pushing by the way it reads. I don't think I can trust the written material, especially since there is little to no source information. If we look at advisory circular 20-165, there is this in the applicability line:

1.1 ( b ) This AC is not mandatory and does not constitute a regulation. This AC describes an acceptable means, but not the only means, to install ADS-B Out equipment. However, if you use the means described in this AC, you must follow it entirely.

Further, 1.1 ( c ) has this line: Applicants using this AC to install ADS-B systems that are not compliant with 14 CFR § 91.227 must follow all aspects of this AC and propose alternate means as appropriate to the FAA.

One more line: 1-2. Who This AC Applies to. This AC is for anyone who is applying for an initial
type certificate (TC), supplemental type certificate (STC), an amended TC, or an amended STC for the installation and continued airworthiness of ADS-B Out equipment.

Experimental has always been a fringe area in aviation, and the FAA always writes rules in regards to standard aircraft. We need to remember, is the small technicality that experimental and LSA rules are governed by their airworthiness certificates, which then extend authority to portions of the regulations.

Also, the FAA's alternate means of compliance is not actually as hard to get as people say. Of course, it is not guaranteed, but the FAA is not going to sit on their butts and laugh at experimental and LSA owners as that will cause a massive amount of backlash and congressional action.

As a result of the tremendous amount of ADS-B misinformation, I am very reserved about reading anyone's blog and comments. Even AOPA writers get articles wrong from time to time and make corrections

[gbigs]

The FAA is at best inconsistent...it's a classic behemoth government circle-jerk.  Since the FAA allows both Experimentals and SLSA to fly without certified avionics it makes no sense they would force a single piece of certified equipment (namely a WAAS GPS) for these two segments just for ADS-B compliance.

 

That's why I am betting when the mandate comes due those flying with ADS-B and the Garmin 796 non certified WAAS GPS will be allowed.  And that's what FD sells today.  The Dynon ADS-B and Mode S xpndr with the Garmin 796.

[Kennith]

Even experimental aircraft must install a certified transponder if flying in Class A, B or C airspace, even if many of the other avionics installed are not certified.  The transponder is the backbone of our aviation safety net, and ADS-B is just the next generation, so there doesn't seem to be any reason why the FAA would allow Experimental or S-LSA to have un-certified ADS-B.

 

A certified WAAS GPS must be able to fallback to GPS with RAIM if it fails the internal check on vertical/horizontal WAAS resolution.  If a non-certified unit could actually do that, then maybe the FAA would consider allowing non-certified GPS, but I seriously doubt it, as this is to be the backbone of our aviation safety.  I cant see any reason why the FAA would compromise that, especially since the FAA has never compromised on the use of a certified transponder.

 

My first reaction to Mac's blog was that it was perhaps exaggerated, until I read the fine print.  It does appear that there is no way for S-LSA to be in compliance, and definitely not for Experimental, at least not at the level of clarity provided for standard category aircraft.  At best, the issue of ADS-B compliance is muddy.

 

It does appear Dynon is banking on non-certified GPS being permitted, but another interpretation is that they can easily upgrade to a certified GPS, just like NavWorx already does, and just like Dynon has already done by installing a certified Trig Mode S transponder with ES.

[Jim Meade]

Here's an FAA document on installation. It only covers part of the questions but gives current thinking.

http://www.faa.gov/nextgen/ga/media/AEA-ADS-B%20Installation.pdf

 

I'm not sure if this is the same AEA reference cited above, which did not open for me, but it may well be. In any case, it is better to have it here twice than not at all so no apologies if it is a dupe.

[Anticept]

I still don't understand where STCs come into play for installing ADS-B systems in experimental and light sport. I DO see where it says that the systems should be listed as compatible from the manufacturers, OR via previous certification effort (this is where an STC comes in).

 

For that matter, the link that Jim provided is saying that experimental and light sport don't even have to be certified (but must broadcast that they should not be used in automated ATC systems by use of SIL/SDA code 0).

 

Unless there is something I am missing, I feel like this is becoming another ADS-B myth...

[Jim Meade]

I think the reference I cited talks about e-lsa and e-ab between now and 2020. Go back and read it a couple of times and see if that makes sense or if I'm wrong. I don't see anywhere that one can put a non-TSO'd system in an e-ab or e-lsa and be legal in the controlled airspace beginning in 2020.

 

But, in the meantime it is legal to put a non-TSO'd GPS driving a ADS-B out transmitter as long as one sets it correctly.

 

The reference doesn't say that directly, but it's the only thing that makes sense to me.

[gbigs]

Even experimental aircraft must install a certified transponder if flying in Class A, B or C airspace, even if many of the other avionics installed are not certified.  The transponder is the backbone of our aviation safety net, and ADS-B is just the next generation, so there doesn't seem to be any reason why the FAA would allow Experimental or S-LSA to have un-certified ADS-B.

 

A certified WAAS GPS must be able to fallback to GPS with RAIM if it fails the internal check on vertical/horizontal WAAS resolution.  If a non-certified unit could actually do that, then maybe the FAA would consider allowing non-certified GPS, but I seriously doubt it, as this is to be the backbone of our aviation safety.  I cant see any reason why the FAA would compromise that, especially since the FAA has never compromised on the use of a certified transponder.

 

My first reaction to Mac's blog was that it was perhaps exaggerated, until I read the fine print.  It does appear that there is no way for S-LSA to be in compliance, and definitely not for Experimental, at least not at the level of clarity provided for standard category aircraft.  At best, the issue of ADS-B compliance is muddy.

 

It does appear Dynon is banking on non-certified GPS being permitted, but another interpretation is that they can easily upgrade to a certified GPS, just like NavWorx already does, and just like Dynon has already done by installing a certified Trig Mode S transponder with ES.

 

FD sells the Dynon SkyView SV-XPNDR-26X Mode-S Transponder  which provides TIS and ADS-B out via 1090ES.  It is NOT TSO'd.  Dynon admits in their lit that in order to be fully compliant one must add a WAAS GPS TSO'd unit.

 

You are not correct about Experimentals being required to install certified avionics equipment - the standard is that Experimentals and SLSA install equipment which performs as well as, but is not necessarily certified.  You may want to read this article from a few days ago from Flying magazine.

 

http://www.flyingmag.com/news/homebuilders-want-answers-ads-b-questions#w1l0mFODQdf6d6D4.99

[Kennith]

 

FD sells the Dynon SkyView SV-XPNDR-26X Mode-S Transponder  which provides TIS and ADS-B out via 1090ES.  It is NOT TSO'd.  Dynon admits in their lit that in order to be fully compliant one must add a WAAS GPS TSO'd unit.

 

You are not correct about Experimentals being required to install certified avionics equipment - the standard is that Experimentals and SLSA install equipment which performs as well as, but is not necessarily certified.  You may want to read this article from a few days ago from Flying magazine.

 

http://www.flyingmag.com/news/homebuilders-want-answers-ads-b-questions#w1l0mFODQdf6d6D4.99

 

 

You are technically correct that, in theory, one could use a transponder that is not manufactured under a TSO authorization, which is a distinction without a practical difference, because 91.215 requires that the transponder must meet the TSO specifiections of either TSO-C47a, TSO-C47b or TSO-C112.

 

No matter who makes that transonder, it still must at least meet the TSO specifications.

 

There is an excellent article by the EAA on this:

 

https://www.eaa.org/en/eaa/aviation-communities-and-interests/homebuilt-aircraft-and-homebuilt-aircraft-kits/frequently-asked-questions/equipping-a-homebuilt-for-ifr-operations

 

If Dynon could show that it's GPS unit does meet the requirements of TSO-C129, perhaps they could satisfy the ADS-B requirements, assuming that the FAA accepts that documentation as equivalent.

[BMcCand - N248CT]

I have a 2006 CTSW, with Dynon D100 and GTX327. These boxes can talk to the Navworx ADS-600-EXP to provide

a consistent pressure alt source (D100) and transponder mode C code setting (GTX). When I last traded mail with

Dave @ FD, I would have to get an LOA for my aircraft type. Plus, I was talking about ADS-600-BG at the time.

 

Navworx now advertises an ADS-600-EXP meeting T SO-C154c
Transmits SDA = 2, SIL = 3. The latter reference a non-public standard for ADS-B,
SIL is System Integrity level. (Accuracy and reliability for traffic sep.)
This is very good news, the prior offering for Experimental had
SDA and SIL of 0, which did not meet the 2020 requirement. See page
http://www.navworx.com/products-ADS600-EXP.php. This is the box for me!  Not sure the
delivery date. Now, If  I could just get Foreflight to talk to it.... or I have to start using Wing-X.