Transponder TT21 versus TT22 - Considerations

On Tuesday, January 20, 2015 at 11:57:33 PM UTC-5, WaltWX wrote:
Daryl,

First, I have no intention of equipping with ADS-B out and agree that there is little or no value to gliders. My interest in having a Trig that is compliant for ADS-B out is just in case FAA changes their mind and mandates it for gliders in 2020. Yes, the complexity of certification and cost are prohibitive. I'm just trying to consider whether it's worth it for an extra $300 and slightly higher power usage to be "ready".

My main interest is to protect myself against fast jets and airliners etc in busy airspace.

Thanks for all your explanations and background in this discussion... although it sure makes a decision on which unit to purchase difficult. I agree the TT21 is probably all I need for the time being.

Walt Rogers WX

If you fly in busy airspace, with airliners and fast jets etc. Please install a transponder. Whether it is a Trig T-21 or TT-22 has really no difference for the usefulness of that transponder. If you intend in future to go though all the money, complexity and hassle (uh why?) of installing ADS-B data-out as well then the question about TT-22 TSO-C166b certification may become relevant.


There is a lot of value in outfitting a glider with ADS-B OUT. Specifically, this is required to reliably receive TIS-B traffic from ADS-B ground stations.

There are a lot of lower cost ADS-B OUT solutions in the pipeline. At OSHKOSH last summer L3 announced a complete 2020 compliant ADS-B IN/OUT solution that was suppose to cost $2-3K. This system was suppose to ship by the end of 2014. I suspect that there will be a number of significant additional product introductions at the next OSHKOSH show.

ADS-B is going to be a very important collision avoidance tool for those of us who fly recreationally near major metropolitan airports, where the mid-air threats are not just gliders, but other GA and airline aircraft.