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-   -   Possible AD for certain NAVWORX ADS-B Units (https://vansairforce.net/community/showthread.php?t=142967)

BobTurner 11-18-2016 06:34 PM

Quote:

Originally Posted by N743RV (Post 1127813)
Here are the comments I posted on the FAA site:

"
1. This Proposed rule will decrease MY Safety!! Without the Navworx ADS600 I will be unable to see other traffic.

2. I rely on my unit to spot VFR traffic and it has already avoided several significant traffic conflicts. Without ADS-B readout in the busy airspace I fly (San Francisco Bay Area) my safety and the safety of my passengers is significantly degraded!!!

3. The estimate of this AD costing only $85 is not based in reality. I have over $8000 of parts and labor invested in my adopting the required ADS-B out requirement and it will cost at least $500 to remove the unit and another $500 to reinstall the Navworx assuming they modify it for free. If I have to buy a new unit that's at least $2500 more. So at a minimum, this Proposed rule will cost me $$1,000 hours and at most $11,500.

4. The proposed rule does not quantify the safety risk of continued operation with the subject hardware. I believe it must be very small, so if the proposed rule must move forward, I would suggest a reasonable period of time to comply with the rule...not "remove the hardware immediately". I would suggest 1 year from AD issue?

5. I suggest that the proposed rule address VFR and IFR use separately. I believe the time to reach compliance for "use only in VFR conditions" should be one year as a minimum and maybe should not even apply to VFR only use!"

Bob Cowan
RV-7a, 400 +hrs

Where did you get the idea that the FAA cares about your safety? They do not (after all, ADSB-in is not required). What they care about is reducing their costs (eventually eliminating radar) and protecting the airlines from you. So they will never agree to let VFR aircraft use less than "perfect" equipment.

DennisRhodes 11-21-2016 03:21 PM

I've been trying to get up to speed on the actual argument of this AD and having a ADS600-EXP P/N xxxx 8013 that's specifically named in the AD, I have a horse in this race. Asking all who have this model installed to go back and take a look at the FAA compliance report data on your original install. Looks like page 5 has the meat on it as to accuracy and SIL and SDA which is all the talk of this AD. First of all the report was 100% compliance as per the FAA. But I was interested in just what the accuracy was /is.

Of all the arguments in this AD my ADSB was reporting well within the requirement of TSO that being .05nm or 304 ft called NACp !! it actually was (better than TSO ) under 98.5 feet 100% of the sample both times. 2455 data points on one test and 1780 points on the other it was 100% under the bracket of < 30meters!!!!! ie 100% compliant!!

The SIL level was shown as reporting 2455 data points and 1780 points respectively ( on the two test) at < 1x10-7 which is at a level of SIL=3 interesting to note none at lower levels. ie 100% compliant!!

The SDA was reported again both test at a level 2 100% of the time ie 100 % compliant!!

By Performance Std set in the TSO it appears to me to meets all Performance Standards of the TSO and that are measured by the FAA .

So whats this all about concerning the 600 EXP model. I have no info on the other models.

I would like to see a plot of others data concerning the questionable parameters but it will take someone smarter that me to plot that out correctly. I will volunteer my data if any takers. Its already public knowledge!! At any rate go back and see what your 600EXP was reporting out at I bet you find it is 100% compliant.

Brantel 11-21-2016 07:05 PM

Quote:

Originally Posted by DennisRhodes (Post 1128388)
I've been trying to get up to speed on the actual argument of this AD and having a ADS600-EXP P/N xxxx 8013 that's specifically named in the AD, I have a horse in this race. Asking all who have this model installed to go back and take a look at the FAA compliance report data on your original install. Looks like page 5 has the meat on it as to accuracy and SIL and SDA which is all the talk of this AD. First of all the report was 100% compliance as per the FAA. But I was interested in just what the accuracy was /is.

Of all the arguments in this AD my ADSB was reporting well within the requirement of TSO that being .05nm or 304 ft called NACp !! it actually was (better than TSO ) under 98.5 feet 100% of the sample both times. 2455 data points on one test and 1780 points on the other it was 100% under the bracket of < 30meters!!!!! ie 100% compliant!!

The SIL level was shown as reporting 2455 data points and 1780 points respectively ( on the two test) at < 1x10-7 which is at a level of SIL=3 interesting to note none at lower levels. ie 100% compliant!!

The SDA was reported again both test at a level 2 100% of the time ie 100 % compliant!!

By Performance Std set in the TSO it appears to me to meets all Performance Standards of the TSO and that are measured by the FAA .

So whats this all about concerning the 600 EXP model. I have no info on the other models.

I would like to see a plot of others data concerning the questionable parameters but it will take someone smarter that me to plot that out correctly. I will volunteer my data if any takers. Its already public knowledge!! At any rate go back and see what your 600EXP was reporting out at I bet you find it is 100% compliant.

The problem is that report only spits out what is being transmitted by the unit in question for many of those reporting variables. SIL and SDA for instance are fixed variables that are determined and output by the device. The report just tells you how many of the received packets had that level of SIL/SDA embedded in them.

That report has no idea what the pedigree of your position source or the SDA of the device actually is....

DennisRhodes 11-21-2016 07:43 PM

So how or who would be able to measure those values ie SIL and SDA if it's not a measurable value? Assume the horiz boundry numbers are actually the measured performance they are talking about. Then I'm confused on how an installation can demonstrate " MEETS PERFORMANCE" without being TSO d via a pedigree from the mfg.

Radomir 11-21-2016 07:49 PM

Manufacturer.... they would have to ensure their equipment meets TSO... it doesn't have to be certified, but proper tests need to be done to ensure it meets TSO.... and manufacturer pencil-whipping it is a no-no in FAA's eyes.

az_gila 11-21-2016 08:28 PM

Quote:

Originally Posted by Radomir (Post 1128453)
Manufacturer.... they would have to ensure their equipment meets TSO... it doesn't have to be certified, but proper tests need to be done to ensure it meets TSO.... and manufacturer pencil-whipping it is a no-no in FAA's eyes.

Actually, I think the whole thing is really pencil-whipped, but with much mathematics, statistics and computer simulations behind the pencil.

Source Integrity Level (SIL) indicates the probability of the reported horizontal position exceeding the containment radius defined by the NIC on a per sample or per hour basis, as defined in TSO-C166b and TSO-C154c.

System Design Assurance (SDA) indicates the probability of an aircraft malfunction causing false or misleading information to be transmitted, as defined in TSO-C166b and TSO-C154c.


I think the above are actually calculations based on some measurements rather than a measured value, after all they are just probabilities. :)

recapen 11-22-2016 09:53 AM

FAA Emergency order suspends -012, -013
 
Just in directly from the FAA

Interesting - doesn't mention the -EXP units - which if I understand correctly contain the same GPS hardware as the -012 and -013 units.

MartySantic 11-22-2016 10:02 AM

Quote:

Originally Posted by recapen (Post 1128549)
Just in directly from the FAA. Interesting - doesn't mention the -EXP units - which if I understand correctly contain the same GPS hardware as the -012 and -013 units.

https://www.faa.gov/news/press_relea...oc&cid=102_P_R

recapen 11-22-2016 10:05 AM

Thanks - I was trying to figure out how to do that!

Mike S 11-22-2016 10:07 AM

Full test in this thread.

http://www.vansairforce.com/communit...d.php?t=143962


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