On Jun 16, 10:30*am, Bret wrote:
On Jun 16, 10:32*am, lanebush wrote:

If it is no longer in the configuration as described in the type
certificate plus any STC 's and/or field approved modifications. *So,
if your winglets are not approved via an STC or field approval (337
form) and are not listed in the type certificate then you are not
flying under a valid airwothiness certificate. *There is the question
of major/minor *modification/repair but I believe winglets would not
pass the test of being excluded from the "major" catagory.

True there are lots of STCs about winglets.

If there is already and STC or 337 for the modification you want to
make on your plane type then you are
on easy street as they have paved the way for your Mod to be accepted
by the FAA.

However reclassing a once certificated Glider as experimental may not
always even be allowed
as one of the other recent discussion topics revealed, in the case of
a DG 505.