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01-04-2017, 01:25 PM
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Join Date: Jun 2006
Location: Delaware, OH (KDLZ)
Posts: 4,196
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Quote:
Originally Posted by MartySantic
Anyone have any idea of the accuracy/inaccuracy of the TSO'd GPS chip vs. the non-TSO'd GPS chips. Are we talking a few inches, a few feet, a hundred feet or a mile. My iPhone shows my position sitting in the kitchen within 10 feet as shown on the Google map.
Will the FAA come clean and discuss this issue, which appears to be the main issue in a response?
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The FAA requires that there is engineering data to support just about everything. The TSO process is a method to provide them specifications and specific data about the device.
I have a non-TSO'd, non-certified GPS in my aircraft that is more accurate and faster response time than my certified GPS which has a TSO. With that said, even though it may be a better GPS, I can't use it for IFR operations. The FARs state that a TSO C146c GPS device is needed for all phases of an IFR flight (terminal, enroute, and approach) if it is the sole navigation device.
The issue with a non TSO certified products is that they are unknown to the FAA. So it's more of an unknown accuracy versus it's less accurate situation.
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01-04-2017, 03:07 PM
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Senior Curmudgeon
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,420
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Quote:
Originally Posted by airguy
Nothing good comes from poking the bear.
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Unless you are the bear-------then it becomes a free lunch 
__________________
Mike Starkey
VAF 909
Rv-10, N210LM.
Flying as of 12/4/2010
Phase 1 done, 2/4/2011 
Sold after 240+ wonderful hours of flight.
"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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01-04-2017, 03:46 PM
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Join Date: Mar 2007
Location: Livermore, CA
Posts: 167
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Mess
I think this whole thing is a huge mess that spiraled out of control.
The FAA claims that the Navworx units need to broadcast a SIL = 0 but AC 20-165 section 3.3.3.3 states that installations that derive their SIL from GNSS position sources compliant with any revision of TSO-C145 should set SIL = 3.
https://www.faa.gov/documentLibrary/...AC_20-165B.pdf
According to Navworx's compliance matrix, all the units in question use a NexNav-mini from Aspen as the internal WAAS GPS source.
http://www.navworx.com/documents/ADS...acted-Copy.pdf
The NexNav-mini is certified to TSO-C145c Class Beta 1.
http://aspennexnav.com/wp-content/up...duct-Sheet.pdf
So unless Navworx is not really using this internal GPS, I don't know why the FAA would require them to broadcast a SIL=0.
It really sounds like this whole thing got personal and spun out of control. I really hope Navworx and the FAA office can both act professionally and work together to come to a reasonable conclusion.
__________________
Chris
RV-8 Wings
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01-05-2017, 07:36 AM
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Join Date: Nov 2006
Location: Savannah, GA
Posts: 1,029
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Quote:
Originally Posted by pukingdawg
Sorry about that....didn't know if they allowed guests access.
Here is a couple of comments. It appears to all boil down to a certification issue, which I understand is very expensive.
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All I can say is that NavWorx had a number of consultants involved in the certification effort. But for the most part, they studied the FAA guidance and proceeded as instructed by that guidance. As best I can tell, the problems started when the "normal thing" at the FAA office was above and beyond what was in the guidance. The alternative (which is a theory I do not like, but must acknowledge as a possibility) is that a competitor influenced the FAA, and once that ball was rolling, it couldn't stop.
Another:
The conversations often went something like this...
NavWorx provides data that is at-least compliant with the regulation.
FAA: This is not what we expect.
NavWorx: Okay, what would you like?
FAA: It is not our place to tell industry how to comply with regulations.
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It would not surprise me in the slightest if this was going on. From my involvement on the engineering side of aviation, it's astounding to me how much otherwise-acceptable stuff (drawings, reports, parts, etc.) gets hung up because of minor paperwork issues and/or "this doesn't fit the usual mold of how we do things". I once had three FAA reps arguing for weeks about whether we could release two versions of a bushing on the same drawing, because one was a standard repair bushing and the other was a new production bushing--but the FAA approval form only allows you to pick one category.
This is why certifying engines/airplanes/avionics/parts is expensive, and why the recently-released Part 23 overhaul isn't going to really do anything for GA costs. The issue isn't designing or building something that complies with the applicable regulations. Rather, it's showing the FAA that you comply with them in the way the FAA wants to be shown.
And that doesn't even get into producing the items in the FAA Way
Quote:
Originally Posted by pukingdawg
That's not to say that I imagine NavWorx is blameless in the situation. I know that in a small town (like the aviation community) you don't mouth-off to the cops, even if you're right. That isn't going to play well for you in the short term or the long. I can easily imagine certain people at NavWorx electing to say certain things to their FAA representatives that I might have chosen not to say.
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That certainly doesn't help.
__________________
RV-7ER - finishing kit and systems installation
There are two kinds of fool in the world. The first says "this is old, and therefore good"; the second says "this is new, and therefore better".
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01-05-2017, 09:47 PM
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Join Date: Oct 2010
Location: Arlington,Wa
Posts: 22
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Called the Feds
I don't know if anyone noticed the contact info for the FAA in Fortworth listed at the bottom of Navworx letter. I decided to shoot them an email. 5 min. Later they replied and invited me to call and discuss the situation with Navworx. I did. Call lasted almost an hour. According to the FAA, they want this resolved without removing all the boxes. I told him that I had 3 boxes in my shop that I was afraid were heading for the dumpster. He told me not to get rid of anything because he believed there would be some solution. Also , to be clear, this has nothing to do with accuracy. As someone mentioned earlier, it is about detecting bad satellite data. I brought up the rumor that Dynon was using the same gps. He said that he did not know because Navworx has never let them look inside their box. They asked if I would let them look at one of mine. All I know right now is that the Feds wanted to talk and Navworx won't. Fishy.
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01-05-2017, 11:32 PM
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Join Date: Sep 2013
Location: Rancho San Lorenzo
Posts: 885
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Good on you, Zlinman. I like your pro-active get to the bottom of things approach with an open mind towards either side's story. I find your conversation with the FAA refreshing after 3 months of gloom and doom.
I hope this does get sorted out well. I like NavWorx and have one new in the box ready to go for my personal RV. Meanwhile I have purchased two FreeFlight RANGRs for two other installs (Husky and Cessna 140) after I waived off the originally intended TSO'd Navworx boxes.
Jim
__________________
RV-8
(a few more airplanes too)
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01-07-2017, 03:19 PM
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Join Date: Nov 2013
Location: Annapolis MD
Posts: 457
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Quote:
Originally Posted by zlinman
.... Also , to be clear, this has nothing to do with accuracy. As someone mentioned earlier, it is about detecting bad satellite data....
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Does anyone know what happens if the unit does not properly detect / handle bad data? Would it calculate a bad position and send it out to other users, or would it simply not send anything? Or choke / need some sort of reset/reboot? Apparently it's a serious concern, but it would be interesting to know the potential consequences of the deficiency.
__________________
CA
2000 RV-8A | O-360, SDS CPI, FP, G3X Touch, VP-X, EarthX | Eastern Shore | KESN
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01-08-2017, 07:51 AM
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Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
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Quote:
Originally Posted by jliltd
Good on you, Zlinman. I like your pro-active get to the bottom of things approach with an open mind towards either side's story. I find your conversation with the FAA refreshing after 3 months of gloom and doom.
I hope this does get sorted out well. I like NavWorx and have one new in the box ready to go for my personal RV. Meanwhile I have purchased two FreeFlight RANGRs for two other installs (Husky and Cessna 140) after I waived off the originally intended TSO'd Navworx boxes.
Jim
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I had same experience talking with Michael at FAA, am cautiously hopeful this matter will be resolved.
__________________
RV-12 Build Helper
RV-7A...Sold #70374
The RV-8...Sold #83261
I'm in, dues paid 2019 This place is worth it!
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01-08-2017, 09:36 AM
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Join Date: Nov 2007
Location: Jesup, Iowa
Posts: 1,657
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Just an observation on my part - -
Since I fly very often, and have had the EXP along with the IFly app on a 10" IPad pro, I will say I have to assume the info sent Wi-Fi to the Ipad is the same as sent out on the 'out' portion. On my IPad, the depiction always seems to be very stable and accurate. When I cross over a highway or such, it shows me exactly at that position. Could it be off 100', maybe, but the value I place on the info is very high. I believe some of the recent accidents near an airport could have been prevented if they had this unit or similar. I always know where to look for traffic, and if it is close ( say under a mile ), I can usually find it. I know I way more often would not have seen it without this device. I feel it is another valuable aid toward safety. I do not want to go without it now.
__________________
John Bender
Flying RV-12 - Serial #120036
Paid in May ( 5-2020 )
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01-08-2017, 12:03 PM
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Join Date: Oct 2006
Location: Foley, Al
Posts: 563
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Hey John, Agree completely. Here is a link to one of my first real experiences with my Navworx ADSB EXP model. It illustrates the benefits of ADSB perfectly. I like your words "high value" regarding the information provided by ADSB. In my view it's an exponential increase in safety!
http://www.vansairforce.com/communit...d.php?t=142426
__________________
Paul Gray
Foley, Alabama
N729PG..... 450+ hrs
RV 7A, Lycoming 0 320 D1A, Sensenich FP propeller
pilotforfun2001@yahoo.com
VAF supporter $$$
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