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FlyingMonkey

GPS working is now a requirement

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https://www.avweb.com/aviation-news/ads-b-preflight-requirement-issued/?MailingID=97&utm_source=ActiveCampaign&utm_medium=email&utm_content=ADS-B+Preflight%2C+Weaponized+Hoverboard&utm_campaign=ADS-B+Preflight%2C+Weaponized+Hoverboard-July+15%2C+2019+(Copy)

This article states that as of Jan 1, 2020, pilots/operators will now have to brief that there is no GPS outage that will affect their intended flight. According to the policy statement from the FAA: 

"If the predicted GPS performance does
not support the proposed flight, the
operator may need to adjust the flight
plan accordingly to avoid the degraded
GPS performance." 

Which leads to questions: What does a pilot do if there is a GPS outage in the area of flight that involved ADS-B airspace? Just not make the flight? That seems to be what the above language dictates. How will that affect commercial carriers? If there's a degraded GPS signal over NYC, are all flights to/from JFK & LaGuardia grounded? What if there is a 400nm diameter circle of degraded performance above 20,000ft (as is common)...must all commercial flights deviate around a 400nm circle to avoid that section of Class A airspace?

This requirement makes non-degraded GPS a 100% requirement for any flight into/through ADS-B airspace, with no recourse or exception, as far as I can see. While I like the safety benefits of ADS-B, I don't see this as a good idea.

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I think there is more to this story. It is too soon to tell what is actually going to transpire if an outage occurs.

I do have a feeling though, GA is going to feel "the squeeze." Too much is at stake in commercial aviation.

For GA, it's a never ending battle to protect our rights in the sky.

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Like with many FAA announcements, I'm speechless.  The illogics just pile one on top of another until the whole of it is uncommentable, lol. For what its worth here's what comes to my feeble mind.

1. Why in the name of God would you intentionally scramble a signal by one branch of government and then mandate that it always work by another? If the government announced that it would occasionally scramble a few VOR signals, the whole weight of the airline business and the FAA would fall on them. So why is it ok to do it to GPS? The answer is that the FAA never cared about GPS and only reluctantly allows it now.

2. How is it possible to be the pilot's responsibility to ensure that the government system is working on his route?

3. How will this ever be enforced, since ATC itself doesn't know where or when these 'outages' will occur?

4. When will the FAA come out with a comprehensive plan for navigation system integrity that outlines required equipment and backups for various activities, ground WAAS backup transmitters, backup frequencies and a rule to keep the Air Force and the CIA/FBI/NSA from messing with the system (as they love to do).

OK, I feel better now ...

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Why can’t they just formulate their regulations in a way that it doesn’t require additional explanatory Notams .. 

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Well, at least they clarified it in a way that's less onerous to us poor puddle jumpers.  But the policy is still going to bite people using non-TSO devices like the EchoUAT from uAvionix.  It specifically states WAAS receiver must have a TSO like TSO-C145 (which my GDL-82 uses) or TSO-C146 to be exempt, and a lot of the smaller companies' devices are without a TSO. 

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I'm not gonna stir the pot on that WAAS GPS TSO thingy,  but I do find it disturbing that my friendly airliner might not have a WAAS GPS on board. And frankly it was my understanding that ALL aircraft hoping to operate in controlled airspace would need ADS-B out by 2020.

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1 hour ago, SportFlyer1 said:

 it was my understanding that ALL aircraft hoping to operate in controlled airspace would need ADS-B out by 2020.

"Controlled airspace" is a misnomer, as that technically includes class E.  The FAA uses the term "ADS-B airspace", which means any airspace where ADS-B is required (Class A, within the boundaries of a Class B, within the boundaries of the inner ring of a Class C, etc).  

Yes, all aircraft operating in ADS-B airspace will require an out installation after Jan 1.  What this latest policy shows is that not all ADS-B installations are considered the same.  TSO'd installs can go about their business, non-TSO'd installs will be required to prebrief for GPS outages and then avoid those areas entirely, even if their equipment is considered to have "TSO equivalent performance".  Which could be really inconvenient since some GPS degradation areas are 400nm across...

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1 hour ago, SportFlyer1 said:

I'm not gonna stir the pot on that WAAS GPS TSO thingy

Not sure what you mean here...what pot is there to stir?

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17 minutes ago, KentWien said:

(Edit: oops, should have read the posts above before responding. )

As I read this, it appears the FAA clarified that it is a non-issue for us?

https://www.avweb.com/aviation-news/faa-clarifies-ads-b-preflights-ga-is-exempt/

IF you are using a TSO'd ADS-B OUT device.  If your OUT device doesn't have a TSO certification, you have to brief prior to flight and avoid any areas of degraded GPS coverage.

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This is going to provide us with hours of entertainment. I like your clear and direct interpretation,  but I have some nagging doubts. When are things ever that clear with the FAA? My reading of the original rule making (which is all but unreadable) leads me to believe that units which have WAAS gps's which meet the performance requirements of the relevant TSO's get a pass on this. Garmin's Bill Stone was quoted as saying that there are zero non WAAS enabled units flying in GA, so they all get a pass. That leaves me with old airliners that have primitive non WAAS units still stuck in their planes, who would have to do this preflight Kabuki dance with the FAA's fancy, non working tool. So I think uAvionics et al are in the clear (at least I hope so).

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Here' the relevant passage in the NOTAM:

Note: It is not necessary for operators of aircraft equipped with the Wide Area Augmentation System
(WAAS) (TSO−C145 or TSO−C146) receivers to conduct a preflight availability prediction. Operators of
aircraft equipped with specific aircraft−based augmentation systems (ABAS) that have been reviewed by the
FAA and are approved for ADS−B operations (i.e., 14 CFR §§ 91.225 and 91.227) also do not need to conduct a preflight availability
prediction.

 

This is a little unclear.  It exempts our TSO-C145/C146 devices, but the second part:

 "Operators of aircraft equipped with specific aircraft−based augmentation systems (ABAS) that have been reviewed by the
FAA and are approved for ADS−B operations (i.e., 14 CFR §§ 91.225 and 91.227) also do not need to conduct a preflight availability
prediction."  

Is a bit vague.  Does that mean devices with "equivalent performance" or something else?  Which devices have been reviewed by the FAA and are approved for ADS-B operations?  How do we know?  Even reading the FARs referenced doesn't really tell me what this means.

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Apparently the whole discussion was to clarify what the FAA would call a violation for (commercial) aircraft that had SA-Aware and SA On GPS systems which they already know will not meet WAAS performance requirements. It looks like none of this would apply to GA craft already required to have WAAS receivers performing to TSO requirements and previously blessed by the FAA. It's all pretty baffling to me.

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