ADSB out in tow planes

On Sunday, June 3, 2018 at 11:15:00 AM UTC-7, 2G wrote:
On Sunday, June 3, 2018 at 1:10:46 AM UTC-7, Darryl Ramm wrote:
On Saturday, June 2, 2018 at 10:38:50 PM UTC-7, 2G wrote:
On Friday, June 1, 2018 at 10:31:39 PM UTC-7, Darryl Ramm wrote:
On Friday, June 1, 2018 at 6:01:43 PM UTC-7, Charles Longley wrote:
One of our Pawnees has an ADSB out transponder now. (Evergreen Soaring) We’ve had glider pilots we’re towing that have FLARM ask us to turn off our transponder. We’ve told the glider pilots to turn their FLARM down or off. My recommendation is to either have a switch for your FLARM or know you can turn the volume down to a suitable level.

The question I have is does FLARM show up on ADSB in?

As discussed here before the solution to spurious PowerFLARM alerts in the glider to the towplane ADS-B Out may be to put a PowerFLARM in the towplane so the PowerFLARM in the glider knows it's a towplane and more tolerant of it being close to the glider. There is unfortunately no way for an ADS-B out signal to contain any information to tell PowerFLARM it's a towplane. The FLARM signal does carry that information. it would be great if somebody could experiment with a PowerFLARM portable in the towplane to see if it indeed does solve the issue.

Be careful turning those transponders off, they provide visibility to other aircraft with ADS-B In, TCAS, ATC, all gliders with PowerFLARM with 1090ES In option etc. And if in controlled airspace its a violation of 14 CFR 91.215... and since the towplane is transmitting ADS-B data for all to see and the signal starts going of in flight that may well get noticed. The likely better option if necessary here is for the glider to turn off or turn down the volume on their PowerFLARM while on tow.

If you have a transponder installed, you are required to operate it at all times unless otherwise directed by ATC (i.e. Oshkosh).

Tom

That's not quite accurate, you are required to operate an installed transponder at all times in *controlled airspace*. 14 CFR § 91.215 (c). So they can be turned off in Class G airspace. Maybe a good aviation quiz night question, or BFR question. But to the point, yes turning them off is a bad idea.

Wrong: 91.215 states where you MUST operate your transponder - it says nothing about allowing a pilot to turn it off. The matter is addressed in section 4−1−20 of the AIM (https://www.faa.gov/air_traffic/publ..._10-12-17.pdf), "Transponder Operation:"

4. Transponder and ADS-B Operations in
the Air. EACH PILOT OPERATING AN AIRCRAFT EQUIPPED WITH AN OPERABLE ATC TRANSPONDER, MAINTAINED IN ACCORDANCE WITH 14 CFR SECTION 91.413 OR ADS-B TRANSMITTER, MUST OPERATE THE TRANSPONDER/TRANSMITTER, INCLUDING MODE C/S IF INSTALLED, ON THE APPROPRIATE MODE 3/A CODE OR AS ASSIGNED BY ATC. EACH PERSON OPERATING AN AIRCRAFT EQUIPPED WITH ADS-B OUT MUST OPERATE THIS EQUIPMENT IN HE TRANSMIT MODE AT ALL TIMES WHILE AIRBORNE UNLESS OTHERWISE REQUESTED BY ATC.

Notice the use of ALL CAPS: the FAA is shouting this requirement out at us. Furthermore, the glider involved in the Minden mid-air collision with the Hawker jet was faulted for not operating his transponder (https://www.ntsb.gov/_layouts/ntsb.a...A277 A&akey=1) even though they were not in controlled airspace at the time.

Tom

(With apologies to John Adams) We are a nation of laws not Aeronautical Information Manuals.

AIM is not a regulation. The 14 CFR § 91.215 regulation is *very* clear. And those regulations, and case law, is what determines what is legally required.

And being told where you are required to do something, also implies where you are not required to. The regulation does not need to discuss the transition between those states that are bleeding obvious. Nobody should be confused that the meaning here is going from required to be on to not required to be on might mean the pilot might... wait for it... ta.. da.. turn it off. And specially since the regulation does not say you cant' turn it off in that transition then you bloody well can.

And secondarily the section of the AIM you are referring to is discussing the provision of ATC services, which relies on transponders and ADS-B out, and if you are receiving those service than what you are quoting above is kind obvious, and fully consistent with 14 CFR § 91.215. Even if it was inconsistent with a regulation FAR/AIM cannot change that regulation or how you are required to comply with it.

I think this is the second time on r.a.s. recently where you quoted stuff claiming it proves some point of yours and instead had you dug a bit deeper you would have seen it was consistent with what others are saying.

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And for those playing along at home...

Of course, in practice turning off transponders and ADS-B Out systems is a bad idea.

Turning off a transponder (unless directed by ATC) in controlled airspace ((everything except Class G) is also a violation of 14 CFR § 91.215.

Turning off an ADS-B Out system (unless directed by ATC) in *any* airspace is a violation of 14 CFR § 91.225(f) "Each person operating an aircraft equipped with ADS-B Out must operate this equipment in the transmit mode at all times." Well that's great given the goals of ADS-B and how it differs from ATC surveillance radar and meaning of controlled airspace.

So if your transponder is also doing 2020 Complaint 1090ES Out then now you can't turn it off in any airspace because doing so would turn off the ADS-B Out.

Ah but now what about TABS ADS-B Out systems? Does 14 CFR 91.225(f) cover that as well? I would say no as 14 CFR § 91.225 is all about regulations applying to "2020 Compliant" ADS-B out systems specified in 14 CFR § 91.227. And if 14 CFR § 91.225 and/or § 92.227 applied to TABS then we have all sorts if other issues. An illogical rat hole that nobody including the FAA likely would want to go down.

Not that any of this actually matters (just leave stuff tuned on) but if it did then a letter to the FAA Office of the Chief Counsel would help clarify this question about TABS. And they tend to take a pretty clear and supportive view of stuff that if it's not really explicit then its allowed (transponder carriage exemptions for gliders come to mind, glider pilots (including me in the past) assumed they might imply more restrictive regulations than they do, the Office of the Chief Counsel on multiple occasions clarified they don't).

See now, hopefully we are pretty well armed for a boozy Aviation quiz night questions about turning off transponders and ADS-B Out. ...