ADSB visibility with non certified GPS

On Monday, October 2, 2017 at 10:50:48 AM UTC-7, Darryl Ramm wrote:
On Monday, October 2, 2017 at 10:16:40 AM UTC-7, Dan Marotta wrote:
Thanks, Evan, but that does not answer the question, either.Â* Sure there
might be certificate action, should a pilot get caught turning on a
not-yet-tested/certified transponder, but it seems to me it would have
been better if the Hawker had gotten a RA from its TCAS box.Â* I know
it's a rhetorical question but then so are a lot of the FARs...Â* I'd
just prefer receiving a letter from the FAA over bailing out (or worse)..

BTW, my transponder was checked by a certified technician within the
preceding 24 calendar months and complies with 91.413(c) and has a
proper logbook entry.

On 10/2/2017 10:26 AM, Tango Eight wrote:
On Monday, October 2, 2017 at 12:16:22 PM UTC-4, Dan Marotta wrote:
Didn't answer the question.

What harm could have come from turning on a not-yet-approved transponder?
Violation of FAR 91.413.

best,
Evan Ludeman / T8

--
Dan, 5J

Dan

Evan is pointing out what is believed to be the pilot's concern here.

My pragmatic safety focused answer is there was little reason not to turn that transponder on, and I would have. The 14 CFR Appendix F to Part 43, ATC Transponder Tests and Inspections required by 14 CFR 91.413(c) only test RF properties of the transponder. There are unlikely to be undetected problems with modern transponders that causes errors in operation or impact other airspace users. And a call to Reno Approach for a transponder check would have been good assurance that the basic transponder operations are working, a good idea on any new install. In some ways Appendix F seems to address concerns of older generation less reliable transponder technology, and specifically to look for know faults that do could impact operation and other users, so still useful to know that stuff is working, and still a 14CFR requirement and should be done.

One thing to note is Appendix F to Part 43 does not check altitude encoder accuracy. And that transponder reported altitude is key to interoperation with TCAS. It's a good idea to check the encoder altitude displayed on your transponder against the altimeter and other sources, or check in with ATC if the transponder does not have an encoder altitude display.

Oh sorry my bad. brain fart, this was a first install so Appendix E to Part 43 applies, which *does* include an altitude encoder test.

I was rushing to try to make a point that regular biannual transponder tests that folks will have done on their glider transponders do not check the encoder accuracy.