GRT Avionics

I just installed a TT22, controlled by the HX, GPS data direct from a 420W (latest software). I pass every ADSB conformance check from the FAA except "Air on Ground". Any ideas? I am showing dual frequency ADSB-in. I heard that used to cause issues, but assumed they've been resolved?

I didn't find an explanation for that box, which was added to newer reports. I think it might have something to do with the TT22 reporting ALT mode for a little while after landing instead of GND mode. To help with that, I made a change to the software. You can try this version.

HX software version 8a-beta18 2016-09-15

Bob,

For what its worth, a Dynon Skyview equipped friend of mine saw the same "Air on Ground" failure in his ADSB performance report from the FAA a couple of days ago. He has the remote Dynon transponder which looks to be just a re badge'd version of the Trig TT22. He wondered if it was because he doesn't have a "weight on wheels" input to the Trig unit to indicate when the aircraft is on the ground. GRT's documentation describing the install and operation of the Trig Transponder mentions that Auto mode switches the Trig xpndr from ALT to GND automatically so maybe making that occur sooner is what Jeff is referring to with the software change he referred to.

I have the FreeFlight Ranger UAT. One of the configuration options is a ground speed threshold that is used in lieu of a "weight on wheels" discrete input to identify when the aircraft is on ground. The PAPR report that I got on 10/31/2016 reported 0 failures for this particular test.

James

I think Jeff has it right. I observed the transponder go from ground to air very promptly on the take-off roll; but on landing, there was a delay of about 50? seconds before it went from air to ground. Hopefully Jeff's software will fix it. I'll download it and re-post here.
If it still has a problem Jeff may have to increase the speed threshold.

Jeff and All,
Thanks for the new software, that seems to have fixed the problem. I just got a "no red" ADSB report from the FAA. Now I have to go fly for 30 minutes (again) in "Rule" airspace, to get my $500 rebate.

Jeff, you should publicize this. The old (current) software did not switch to ground from air until about 50 seconds after landing (I watched the HX display). New software switched while still on the runway, much quicker. I don't know what the FAA standard is to get a "pass" but clearly the old software didn't make it, the new beta one does.

Bob

Can I use this Beta on an HxR?

If not, when will we see a Beta that corrects this issue for HXr?

I spoke too soon. Today I once again failed the 'air on ground' test. I landed into a pretty good wind, and let the plane roll down the runway to the taxiway. The transponder stayed in air mode until I turned off the runway. I guess the IAS stayed too high too long.
Jeff, is the software using IAS to switch? Any chance the change over value can be user-programmed? It's clearly set too low for me. On my previous 'pass' result, I braked hard to a full stop on the runway, to get it to switch over as soon as possible.

I have an HXr with T22 and Garmin GNS 480 (all current software and appropriate wiring).
I just generated a report for a flight after installing the Beta.
The only "Red" was Air on ground
Air on Ground
14.69%% Fail

Many airports are now requiring Transponders on "ALT" at all times on the ground.

How will this affect the ADS-b compliance?