GPS Working is now your responsibility

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MrMorden
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GPS Working is now your responsibility

Post by MrMorden »

https://www.avweb.com/aviation-news/ads ... %28Copy%29

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 of 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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TimTaylor
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Re: GPS Working is now your responsibility

Post by TimTaylor »

I guess, if you need ADS-B out to fly in class A, B, and C airspace, you can't fly in class A, B, and C airspace if the system is not working. You need to use the provided tool as part of your preflight routine to make sure the system is working. If it's not working, alter your flight plan to stay out of class A, B, and C airspace.

Thanks for posting this and the links. I have added that site to my desktop and will add to my iPad and iPhone.
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Type47
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Re: GPS Working is now your responsibility

Post by Type47 »

Nice bait and switch...
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Warmi
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Re: GPS Working is now your responsibility

Post by Warmi »

I guess FAA is attempting to ensure properly functioning ADSB functionality is considered essential for safe operation in relevant airspaces.
I guess, it is like having a primary airport surveillance radar being out at a major airport - can the airport operate or do they reroute flights somewhere else ?
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MrMorden
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Re: GPS Working is now your responsibility

Post by MrMorden »

TimTaylor wrote:I guess, if you need ADS-B out to fly in class A, B, and C airspace, you can't fly in class A, B, and C airspace if the system is not working. You need to use the provided tool as part of your preflight routine to make sure the system is working. If it's not working, alter your flight plan to stay out of class A, B, and C airspace.

Thanks for posting this and the links. I have added that site to my desktop and will add to my iPad and iPhone.
Sure, I understand that, and it's not a big deal for us "little fish" that don't have critical missions to perform. But what about airlines, that get dinged by the FAA for not meeting arrival or on-time statistics for their routes? Are airline passengers going to accept "Nobody can go to New York City today because GPS is acting up"? Or what about an air ambulance, that can't take off under the Class B to get to a crash site...does that poor guy bleeding out just die at the scene to make sure nobody flies without GPS, even if such a flight can be made safely?

I think there are serious questions with this policy statement.
Last edited by MrMorden on Tue Jul 16, 2019 9:42 am, edited 1 time in total.
Andy Walker
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Re: GPS Working is now your responsibility

Post by MrMorden »

Type47 wrote:Nice bait and switch...
I won't go that far, but it does seem to feed fears that the ADS-B mandate might be used for more than just enhancing safety. Primary radar is still in place, I don't understand why in a GPS-degraded state we can't just drop back to the way we've safely been operating for 50 years. It sure beats creating essentially giant TFRs that affect all traffic from the ground up into space.

If they insist on this scheme, they should merge this with TFR generation and create TFRs that indicate what flight areas are GPS-degraded and closed to what traffic. Asking pilots to interpret a GPS coverage map and decide if an area is degraded enough to affect their flight is a recipe for pilots to get violated, even if they have done the due diligence of checking the website.
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Re: GPS Working is now your responsibility

Post by MrMorden »

Warmi wrote:I guess FAA is attempting to ensure properly functioning ADSB functionality is considered essential for safe operation in relevant airspaces.
I guess, it is like having a primary airport surveillance radar being out at a major airport - can the airport operate or do they reroute flights somewhere else ?
Yes, except that ADS-B is still backed up by primary radar. If the GPS part of ADS-B is not functioning, why can't we default to the way we are safely operating flights right now? It's got to be better than closing off huge swaths of airspace to all traffic!
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Re: GPS Working is now your responsibility

Post by TimTaylor »

Sounds like they are getting ready to shut down the radar and go 100 percent ADS-B.
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Re: GPS Working is now your responsibility

Post by dstclair »

There is an exemption already in place through 2024 that the airlines will no doubt use:
In April 2015, Airlines for America
(A4A) petitioned the FAA, on behalf of
A4A member airlines, for an exemption
from the Navigation Accuracy Category
for Position (NACp) and Navigation
Integrity Category (NIC) requirements of
the rule. In August 2015, the
Administrator issued Exemption No.
12555, a time-limited grant of
exemption from § 91.227(c)(1)(i) and
(iii) for the period from January 1, 2020
through December 31, 2024. Exemption
No. 12555 permits operations in ADS–
B Out rule airspace during periods
when the GPS position provided to the
installed ADS–B Out equipment does
not achieve the required accuracy or
integrity performance, provided certain
conditions and limitations are met.
For those aircraft meeting the
performance requirements of TSO–C196
(SA-Aware), the operator is not required
to perform a preflight availability
prediction prior to conducting an
operation under the exemption.....
As I read it, us little guys are exempted as well if your ADS-B GPS is TSO-C196 certified (mine is).
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MrMorden
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Re: GPS Working is now your responsibility

Post by MrMorden »

dstclair wrote:There is an exemption already in place through 2024 that the airlines will no doubt use:
In April 2015, Airlines for America
(A4A) petitioned the FAA, on behalf of
A4A member airlines, for an exemption
from the Navigation Accuracy Category
for Position (NACp) and Navigation
Integrity Category (NIC) requirements of
the rule. In August 2015, the
Administrator issued Exemption No.
12555, a time-limited grant of
exemption from § 91.227(c)(1)(i) and
(iii) for the period from January 1, 2020
through December 31, 2024. Exemption
No. 12555 permits operations in ADS–
B Out rule airspace during periods
when the GPS position provided to the
installed ADS–B Out equipment does
not achieve the required accuracy or
integrity performance, provided certain
conditions and limitations are met.
For those aircraft meeting the
performance requirements of TSO–C196
(SA-Aware), the operator is not required
to perform a preflight availability
prediction prior to conducting an
operation under the exemption.....
As I read it, us little guys are exempted as well if your ADS-B GPS is TSO-C196 certified (mine is).
Are you sure you're exempt? I have a TSO'd unit (Garmin GDL-82), but the TSO listed in the manual is TSO-C145d and TSO-C154c, NOT TSO-C196 referenced above.

The fact the exemption has an expiry date indicates to me they want to do more. That the exemption was issued well in advance of this policy makes me think that there might have been a plan all along to use ADS-B to push as much GA traffic as possible out of ADS-B airspace. I could see this progressing to "non-TSO equipment doesn't qualify for entry into ADS-B airspace" and then to "All VFR traffic must be on a flight plan in ADS-B airspace" to "VFR traffic is not permitted into ADS-B airspace regardless of equipment".

Time will tell.
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JJay
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Re: GPS Working is now your responsibility

Post by JJay »

New NOTAM now says GA aircraft are exempt from this whole mess as long as they use WAAS GPS source (and all ADSB-In solutions certified for 2020 mandate use WAAS).

https://www.avweb.com/aviation-news/faa ... 17%2C+2019
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MrMorden
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Re: GPS Working is now your responsibility

Post by MrMorden »

JJay wrote:New NOTAM now says GA aircraft are exempt from this whole mess as long as they use WAAS GPS source (and all ADSB-In solutions certified for 2020 mandate use WAAS).

https://www.avweb.com/aviation-news/faa ... 17%2C+2019
Well that does make some more sense, and I'm glad it specifically references TSO-C145. There was language in the policy I linked than non-WAAS GPS was much more vulnerable to position errors when there is a GPS degradation. But it looks like even WAAS receivers that are not TSO'd will still be affected. I don't know how many folks are using non-TSO devices, but I know that some of the uAvionix boxes (like the EchoUAT) and other popular devices for experimental and light sport aircraft do not have TSO certifications.
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Re: GPS Working is now your responsibility

Post by drseti »

MrMorden wrote: other popular devices for experimental and light sport aircraft do not have TSO certifications.
For experimentals and LSAs, there is no requirement that the WAAS position source and Mode S Extended Squitter transponder hold a TSO certification. However, to pass the ADS-B validation test, they must be TSO performance compliant.

I can't speak for all equipment providers, but in the case of Dynon (whose products I use), their systems for LSA and Experimental do meet the TSO performance specs.
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MrMorden
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Re: GPS Working is now your responsibility

Post by MrMorden »

drseti wrote:
MrMorden wrote: other popular devices for experimental and light sport aircraft do not have TSO certifications.
For experimentals and LSAs, there is no requirement that the WAAS position source and Mode S Extended Squitter transponder hold a TSO certification. However, to pass the ADS-B validation test, they must be TSO performance compliant.

I can't speak for all equipment providers, but in the case of Dynon (whose products I use), their systems for LSA and Experimental do meet the TSO performance specs.
There is no requirement, correct. But according to the new policy statement after Jan 1 if your equipment does NOT have a TSO, and you are planning a flight through ADS-B airspace, you must brief GPS availability before your flight and change your planned flight to avoid areas of degraded GPS performance, if your planned route takes you through such areas. Not doing so and flying through such an area will result in a violation.

Meeting TSO specs is not sufficient here, by what I read. The equipment must be TSO'd to be exempt.
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Re: GPS Working is now your responsibility

Post by Type47 »

This is the bait and switch I am talking about.
We equip based on all current information, before the deadline, at great expense and now they have decided to move the goalposts.
How many of us would have chosen a different option if we had known?
The tso solutions are only a few hundred more dollars.
If you are spending $2000, $2500 is not that much more for a system that is accepted.
Who would spend $500 more for no reason?
Bait and switch.
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