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Garmin GTX327 and GDL82 glitch

OKAV8r

Well Known Member
I installed a GDL-82 with fail lamp and anonymous switch in an airplane 6 months ago. Paired to GTX-327 transponder. System checked out fine at the time of install.
Now, the owner reports that anytime he is instructed by ATC to "Ident", the GDL-82 fail light illuminates for about 1 minute. During that time, foreflight ownship verifies the GDL is not transmitting. GDL-82 has the latest firmware...

Anyone with similar setup out there that can report their system performance?
 
Was ident not triggering the light before or was this the first time an ident was requested since install (idents are not as common for VFR flights as they are on IFR flights)? Here are a couple of ideas. When the GDL 82 senses and ident from the transponder it initiates a Special Position Indication pulse for 18 seconds (SPI). Prior to that pulse time the GDL 82 is 1.) stepping out of the way of the ident so the transponder can send the traditional ident out unfettered, and 2.) then transmits this SPI over the ADS-B network. I am unclear as to if an SPI is only sent to ground stations or if it also goes to other ADS-B aircraft for re-broadcasting with the TIS-B system like standard reports. And so in scenario 1 above with the GDL 82 stepping out of the way and opening up the signal path for the transponder it would stop sending out the standard 1-second position updates during the ident and then start sending out the SPI after the transponder is done identing.

But on a more basic level, if there is something wrong with the approved out equipment (GDL 82) the FAA red light camera computer will send out a notice to the registered aircraft owner's postal address without hesitation. So no notices means no problem. I have seen a notice show up for a Comanche owner who momentarily flipped his nav lights off (and hence his uAvionix SkyBeacon off) to see his landing gear lights on final. So no complaints from ATC or the nanny computer would mean things are good. In this case I would just consider the ADS-B fail light to double as an ident light.
 
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