FWIW, the person at the DGAC responsible for Socata stuff has been a Madame Klinka. I got a special letter from her in 2005 stating that my TB20 met FAA requirements when built, which avoided an Export CofA. It took a long time to track her down, and I don’t know if she is still there. I found the DGAC switchboard just hangs up when they hear an English speaker.
The contact at Socata Tarbes is Francois Blume. Sometimes they reply quickly but in general with Socata you need to allow perhaps a year to get a reply, with several identical emails and faxes sent in over time. Most people who worked on the TB range have retired and I would think everybody who worked on the earlier ranges has long gone. So if you have a long term project, start early…
Installing avionics not covered by an STC (where the install is an EASA Major mod) is very difficult on EASA-reg aircraft. There is a process but you have to throw a few k minimum at an EASA 21 company. I went through this in 2003 (on a really small minor mod) and gave up when it would have cost about 5k (it was done as a Minor mod when I was N-reg). One guy wanted to change the type of oxygen cylinder in his G-reg TB21 and spent I think close to 10k on the EASA process.
However if you are N-reg and Europe based, the “non-STC route” for a Major mod (which is usually a Field Approval) is difficult too. I have done it twice. See the notes here and here. The way around the Field Approval involves a DER (form 8110) which also costs money (4 figures, unless you can do your own design work and have good connections).
That is why Garmin own Europe now. They magically managed to get EASA to accept the idea of AML STCs.
I agree, to get information from DGAC or Socata one can best ask a native French speaking person, I don’t have any knowledge of the French language.
The problem is that Part 21 seem to over engineer their design changes, it is all very detailed, which cost lost of time in the design. There a several levels within Part 21, but all of them are very expensive. Even Part 21 certification cost (charged by EASA) for the lowest level (which only allows to approval minor changes for a restricted field) is quite exessive and doesn’t make up for the cost for EASA fees if you have them doing the minor mod approval even if one does at lot of them.
Basically the Part 21 route is not interesting in most cases.
The main problem is that one can’t do major changes directly with EASA (or which I would think is more appropriate, is that these changes should be classified as minor change).
Note Garmin is not the only one with this AML, their are lots of others with AML approvals even some years ago. It only seems that more and more is considerd major, which was considered minor in the past. So these companies will have to get AML approvals to get their products sold, else the certification costs for each customer would exceed the cost of the equipment + installation.
Jesse, yes I have a T67c
I believe the T67M260 might be on the AML
@ Peter: Thank you, I had contact with several people at Socata in the past. They were moderately helpful, but basically they know not much about the ST-10 and prefer to be left alone with this exotic aircraft model.
If only they had made an Annex II aircraft out of it, life would be much easier 
…
yes I have a T67c
They have insured me that this would be updated with the next revision, this shouldn’t be a problem, as the basic airframe is allready approved, for some reason, one model / engine combination within the TCDS got not listed.
If only they had made an Annex II aircraft out of it, life would be much easier …
Reading this Special airworthiness specification for Socata ST10 Diplomate it seems that just is wat the DGAC did for years, while they are now some kind of EASA aircraft (not full annex I) either. I don’t know why this changed, as DGAC found them EASA aircraft, or that EASA found that they were EASA aircraft.
If DGAC would still be responseable for design changes, it could be that you have lucky. I would recommend you to find out with DGAC if they can accept design changes for you aircraft, knowing that might be usefull knowledge for your specific aircraft in the future.
Jesse, many thanks for your efforts.
I’am aware of that EASA document and was in contact with a guy from DGAC two years ago. Back then, it was about replacing the brake system. He told me there’s not much they can do for me (even though I asked in French ), as EASA objected to the type being put under Annex II. According to him, they only managed to secure that privilege for the grandfathered build numbers mentioned in the document.
