I received an answer directly from Trig today in response to an e-mail
that I sent yesterday.

Trig says that the TT21 "is not yet legal for use in FAA approved
aircraft". Trig is actively working on FAA TSO approval (they already
have European TSO certification), but they say that any date they
might give for FAA approval "would be nothing more than a very very
rough estimate". As for SEA stating C112 and C88a certification, Trig
says that that is a mistake and that they will contact SEA about it.
They feel that SEA wrote that in anticipation that they "will have a
TSO sooner or later".

Trig also says that if I "can wait several months it [will] certainly
[be] worth the wait". I think I'll be doing just that...

-John

On Jun 21, 12:54 pm, jcarlyle wrote:
The key question for use in the USA is of course FAA TSO approval, and
as you say there isn't a clear answer to that question. I suspect Paul
Remde is correct that it hasn't yet gotten FAA approval, since SEA
says "now accepting TT21 orders" in a 5/28/2009 brochure, and more
importantly, you couldn't find it in the FAA database. However, SEA
does list TSO C112 and C88a approval on their TT21 catalog page! I'll
call SEA tomorrow and try to find out the true story with regard to
FAA TSO approval.