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  #1  
Old 01-03-2018, 09:15 AM
jaustinmd jaustinmd is offline
 
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Location: Pikeville, TN
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Default Public ADS-B Performance Report Interpretation

Although there is a User's Guide published by the FAA to accompany the Public ADS-B Performance Report (PAPR), I still have difficulty interpreting my PAPR reports. Obviously, any parameter flagged red on the report is a problem, but I'm not sure what the FAA considers a "pass" when the total report is taken into consideration. NOTE: I'm NOT discussing testing for purposes of claiming an ADS-B installation rebate, but rather whether I have a basically satisfactorily-performing ADS-B installation or not.

Here's a specific example: I recently installed an ADS-B "out" device and have received at least two totally clean PAPR's with 0 errors in all parameter boxes. OK, that's great, BUT subsequent to that, I recently had a short flight (14 minutes) with a "Missing Elements" NACv error red-flagged (which I understand to be a GPS velocity parameter). It indicated a "13.55% Max Fail" with the maximum duration of the error (Max dT) of 1 min 48 seconds and 110 maximum consecutive failures (McF). All other parameters in the report had 0 errors.

However, earlier in the same report, it reported under "Exceptions" that NACv was "No," which according to the User's Guide, "No=Pass."

The User's Guide is confusing because on page 7 it states that a NACv Exception is whether the "aircraft failed to meet the performance standards of the identified parameter: Yes=Fail, No=Pass." Then, on page 8, where the Guide discusses "Missing Elements," it says "Missing Elements will be highlighted in red if the aircraft fails to meet the Performance Requirements."

So, am I to interpret that since there is no NACv Exception, that overall, this is a satisfactory/passing report? Does this mean that although the NACv parameter had a significant % error, the percentage was relatively high because it was such a short flight and therefore, not really of concern?

I'm hoping there's someone out there who is very familiar with these reports and can comment. If anyone can point me to a "plain-language" explanation of the PAPR reports and the significance or not of the various parameters, I'd really appreciate it!
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Last edited by jaustinmd : 01-03-2018 at 09:21 AM.
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  #2  
Old 01-03-2018, 09:42 AM
jaustinmd jaustinmd is offline
 
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Quote:
Originally Posted by rv7boy View Post
John, it's been a couple of months since I flew my test flight. In my case, and in many others, the FAA was very prompt in sending me an email explaining my test flight score. Since I did not fly in Class B or C airspace and did not communicate with controillers, I knew ahead of time that my report would be delayed. But my final "OK" for my flight came about a week later.

I'm sorry but I can't interpret your test scores, but I do believe if you'll wait a few days, the results will be in your inbox.
Just to be clear, I'm talking about submitting a request for a PAPR to evaluate my installation, NOT in conjunction with application for a rebate. I do very promptly receive an email with an attached PAPR report, but there is NO interpretation by a human - just parameters red-flagged if there are errors. I know you can request a review/"manual interpretation" by a "real person" at the FAA, but no interpretation is sent automatically. Even when I have requested a "manual interpretation," they indeed do state if it is "OK" or not, but really don't go into explanation of errors and typically say "contact your avionics manufacturer or installer."

I'm just trying to get a better understanding of what constitutes a "pass" or "fail" and what significance, if any, individual parameters constitute. I guess my basic question is that if there are no "Exceptions" in the report, despite individual parameters being red-flagged, is it a "passing" report? I'll see if I can ask that specific question on a manual review and see if the tech answers definitively.

Thanks,
John
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Last edited by jaustinmd : 01-03-2018 at 09:46 AM.
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  #3  
Old 01-03-2018, 09:47 AM
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rv7boy rv7boy is offline
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After re-reading your post, I realize I probably should not have replied. Thus, I deleted my post. Hopefully, someone can provide the assistance you are requesting. Sorry for the quick trigger fingers.
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  #4  
Old 01-03-2018, 12:11 PM
jaustinmd jaustinmd is offline
 
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Well, I emailed the PAPR for manual interpretation and here's the FAA's response:


The good news is the reports are easy to read because if there is red ANYWHERE that means the ADS-B system is not meeting performance standards (failure). However, there are exceptions and one is fringe of coverage due low altitude flying/mountains. In your case, it appears the red is due to low altitude (below 2000 ft) and lack of ADS-B coverage. I suggest you check the system again after a few more flights. It appears your system is functioning correctly.


His assessment is correct in that the flight started at low altitude (but, I've had 2 "perfect" PAPR's following the same flight profile). So, I guess one can't assume too much and has to request a manual evaluation anytime there is a failure to find out if it is significant or not! I certainly appreciate the FAA's prompt and personal response!
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  #5  
Old 01-03-2018, 02:12 PM
rv8ch rv8ch is offline
 
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Quote:
Originally Posted by FAA
... In your case, it appears the red is due to low altitude (below 2000 ft) and lack of ADS-B coverage. ...
Don't all flights start and end at low altitude? :S
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  #6  
Old 03-08-2018, 08:15 AM
Tango Mike Tango Mike is offline
 
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I've been flying around with a fully compliant ADSB system for a couple of years now, and up until two days ago, I hadn't even heard of a PAPR. Then a certified letter from the FAA showed up with $5.37 worth of stamps covering the right side of the envelope that someone manually applied. My initial reaction was that the contents must be really important, and what did I do to attract the attention?

The letter is dated January 19, 2018, and it informs me that a flight on January 4th failed to meet performance requirements. The report has red highlighted columns in the integrity and accuracy sections, and I'm instructed to reference the latest PAPR User's Guide to review the report and contact an Aviation Safety Inspector so he can provide me with additional details associated with the notification.

The flight in question logged .4 hrs, remained in the traffic pattern, never climbed above 1000' AGL, and flights conducted since then haven't generated any further PAPR letters. At least I don't think so, but with a delay of 3 months between the referenced flight and receipt of the letter, who can tell?

It appears that we have a new monster in our midst, spring-loaded to react on a flight-by-flight basis, as opposed to waiting for a series of flights in which failure to meet performance requirements for a specific aircraft can logically be attributed to onboard equipment malfunctions.
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