I will add my two cents here as I am converting a C-reg aircraft into a N-reg.
Our local FAA FSDO will not accept any major alterations and repairs that were done in Canada. This aircraft had a panel upgrade and a few modifications which were all done through STC’s while it was in Canada under C-reg. During the conformity check, our FAA rep did not accept any of this and I have to create a new Form 337s for every modification done in Canada. I have to complete 13 different 337’s for this aircraft. Essentially I have to accept the liability and accept ownership of all this work that was done prior.
I would have a hard time agreeing that EASA modifications would be accepted by the FAA and vice versa.
Any news on this? Can the TRX-1500A be installed on an N registered aircraft in 2017?
In the USA, autopilots, EFIS, and some other bits, plus AIUI anything which alters the aircraft perf figures in the POH, require a TC or STC and cannot be done as a Field Approval, or a DER job
(My bold added to highlight the detail to which I’m posting a response)
That may be true as an FAA policy now, or not, at some FSDOs 
As always and given that there’s no law against it, I think there are exceptions. My N-registered plane has a field approved propeller change without POH changes, and the performance figures are now inapplicable. It doesn’t make much difference to me because when I need hot and high takeoff distances and refer to the POH, no such data exists. You can choose hot (ish) or high (ish), but not both simultaneously! The manufacturer presumably had nowhere to test at high density altitude.
Other older planes (like my plane number 2) were certified with no POH so there is nothing to update.
Unless ready to pay to have an EASA STC made right ?
That’s one way but it’s an overkill – unless the said equipment cannot be installed without an STC. In the USA, autopilots, EFIS, and some other bits, plus AIUI anything which alters the aircraft perf figures in the POH, require a TC or STC and cannot be done as a Field Approval, or a DER job. In EU-land, I don’t know.
Normally you would get the mod recertified by an EASA 21 company. Some years ago I dealt with one on a little project (a backup oil temp gauge) and they wanted £2000 just to sign off the design, and that was assuming me doing everything “right”.
And I suppose for now there is no “easy” way to get that done…
But aren’t they planning on simplifying this ?
There is no mutual STC acceptance… I don’t know of anybody who knows any more. It would demolish the EASA 21 “sales of STCs” business, and since many people working at Cologne are from EASA 21 companies… 
What I have recently read is that FAA and EASA are accepting each other’s STCs at a registry transfer.
So if e.g. you have an N-reg with a mod which has an FAA STC but not an EASA STC, and you are transferring it to G-reg, that STC will be accepted. And vice versa.
Very interesting to read for one possibly looking at buying an N-reg in the USA as well
As before, acceptance of STCs after a registry transfer (e.g. installing FAA STCd equipment on a G-reg) remains a no-go.
Unless ready to pay to have an EASA STC made right ? And I suppose for now there is no “easy” way to get that done…
But aren’t they planning on simplifying this ?
What I have recently read is that FAA and EASA are accepting each other’s STCs at a registry transfer.
So if e.g. you have an N-reg with a mod which has an FAA STC but not an EASA STC, and you are transferring it to G-reg, that STC will be accepted. And vice versa.
I believe the same also applies to FAA Field Approvals (for which there is no EASA equivalent, AFAICS).
Can anybody confirm this, with a primary reference? It ought to be in some FAA-EASA treaty.
It seems to be an official process for doing stuff which used to happen anyway to a fair degree. Recently I was talking to an old maintenance guy here who said he oversaw a load of N to G transfers in the 1990s in which basically everything was accepted by the UK CAA. This was suprising since the UK CAA would normally be expected to require any non-UK certified (this was before EASA’s 2003 “certification unification”) mods to be either ripped out, or recertified by a CAA L2 company (£ 4 figures).
It is highly relevant to many people looking at installing equipment on their N-reg but who are reluctant to do so out of concern that the market value will be damaged if it can never be transferred to a Euro registry. Or vice versa.
As before, acceptance of STCs after a registry transfer (e.g. installing FAA STCd equipment on a G-reg) remains a no-go.
From my memory, in the past the FAA had a (bi)lateral agreement with some countries, UK, Netherlands, France, Germany and Sweden as I recall, could be more. This agreement is an EASA agreement, as such it contains far more countries.
Not sure on the AOC part.
There is some limitations on critical PMA parts, non critical PMA are in general no problem for EASA.
It seems to me FAA has long been open to accepting European STC data, but in the past it was on a one-time basis. My European manufactured propeller was installed on an N-register plane with a one-off FAA field approval, about 15 years ago, using a German STC as engineering data. I don’t know how hard it was to achieve because I didn’t own the plane, I just have the 337 package. No DER was involved, only the then-owner armed with the German STC and written support from the propeller manufacturer.
Access to European market for certain FAA PMA parts for example
That has always been the case. PMA parts are widely used in Euro-reg GA aircraft. For example when I was G-reg I had an MD26 400Hz inverter installed for the KI229 RMI. The MD26 was a PMA part. Most scheduled service parts like filters are PMAd.
I recall hearing that PMA parts are banned for AOC aircraft (which have to be maintained by a 145 company) but I don’t know anything about that.
So what has actually changed? Is it the AOC position?
The other way around, American can use the FAA to get their EASA TC or STC
There was an older (I think from c. 4 years ago) treaty which allowed for mutual acceptance of data used to obtain an STC (not the STC itself – that would be dynamite).
What has changed here?
