GRT Avionics

MustangUSA wrote:I will be sure to get the new SX update installed as soon as my avionics tech installs my new system. OR..... do I need to go ahead in pre-install it in the Sport SX 200A before the TT22 is installed?

Install it before you fly with the SX and TT22. It only affects how fast the SX switches the TT22 between GND and ALT modes.

OK... Thanks Jeff... Will do.

I recently purchased a Legend Cub and want to install minimal ADS-B Out. i.e. No "TV" screens.
Can I use the Trig TT-22 and Safe-Fly 2020 GPS as an ADS-B, stand alone solution?

Mel, can you install a weight on wheels/squat switch? Maybe on the tail wheel? If so, I know the answer is yes. But with no squat switch, I don’t know if the Trig has software to switch based just on gps groundspeed. I do know that Trig sells an airspeed switch for this purpose (you need to tap into the pitot line). About $100 iirc.

The latest TT22 manual suggests the TT22 can switch based on ground speed in the standalone configuration but I don't know anyone who has that working yet. It works with an EFIS as controller, which also provides airspeed data. The official solution (for certified aircraft) is to use an airspeed switch.

Thanks Guys, I'll continue my research.
The Garmin GTX 335/GPS, the Appareo Stratus ESG, and the SkyBeacon all claim to be complete solutions. How do they get around the switching problem?

I *think* they all switch on gps ground speed. What other data do they have? I can tell you that after my TT22/HX installation the only ‘fail’ I got was this issue - fixed after GRT modified their software to allow me to set reasonable air and ground speed thresholds, for the -10. With a Cub you have a particular problem: there will be times when your ground speed is near or at zero, but you will be airborne. I suspect you will need an airspeed input (or squat switch) to get satisfactory results in varying wind conditions.

The echoUAT can switch with only ground speed if it is operating without an EFIS, but I know they want other air data when it's controlled by an EFIS.

The air/ground speed setting we added wasn't the solution. It turns out the TT22 does not switch the ADS-B air/ground mode with the transponder air/ground mode because the FAA requires ADS-B transmitters use an automatic system for this determination (speed or squat switch). So Trig added a virtual squat switch mode that can use AHRS and GPS data. The EFIS now has a Squat Switch setting for "AHRS and GPS data" when it's the controller. The EFIS sends some air data to the TT22 through the GRT adapter (requires Adapter Software version 5). I don't have any information on how this works with the Trig control head.

Today I talked to a customer with a new TT22 control head and his unit had an "Auto" "use GPS data" option for the Squat Switch setting. Both the control head and remote unit must need recent updates for that to work. I don't know what versions you need.

Thanks Jeff. I'll be purchasing "new", so hopefully this will all be good. My next Xponder cert is due in June, so I'm looking at that time frame.