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How could this item be legitimately repaired? Gull Airborne Fuel Conditioner. (also legal amateur avionics repair)

Yes….another “don’t ask, don’t tell” situation…. I presume this is a purely “hypothetical” trimpot…right??

YPJT, United Arab Emirates

The issue is real but the repaired item will not be installed; it will end up on the shelf as a spare, AFAIK. The owner found a working part from some parted-out plane.

Interesting that none of the people who I know should know the answer have posted… I guess 146fixer might be nearest the mark in saying that (since the company is long gone and there are no known manuals) there is no legal repair possible.

I am just amazed that it isn’t possible to set up a 145 company with the authority to diagnose and repair stuff like this. That proposition flies in the face of qualifications like Part 21 or DER.

To re-state: I am not asking about unofficial methods. I know how those work. The subject header asks about “legitimately”.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

Interesting that none of the people who I know should know the answer have posted….

That will be the"don’t tell" part…

YPJT, United Arab Emirates

OK- I’ll have a try.

Part 21J DOA (we’re talking EASA here) only covers aircraft-level design/certification, not equipment level. For certified equipment design, the organisation needs to hold an AP-DOA (alternate procedures) with specific approvals against particular equipment TSOs.
It’s slightly different for non-TSO’d role equipment (cameras etc),where no specific equipment design approval is needed – the aircraft level 21J using the part within an installation project takes responsibility for the parts.

Therefore, as a starting point for this broken component, a 21J DOA can’t help. Next problem is that one design company (AP-DOA) can’t alter someone else’s TSO’d product without either the written approval of the TSO-holder (unlikely in this case) or by taking full design responsibility, so they re-qualify the part and give it their own part number.

So, how to deal with this particular broken component. Find an AP-DOA with appropriate certification capability to approve the change under their own part number and then provide the approved data to a workshop with the correct Part 145 ‘C’ rating to be able to repair the component and release it to service.

A final alternative is to apply to directly to EASA for a Minor repair – no DOA involved. Anyone can apply and EASA will directly approve the data. I’ve done this in the past for a Fuji airframe part where no maintenance data existed. Once the data is approved by EASA, then as above, give it to an appropriately rated Part 145 to embody the change.

Avionics geek.
Somewhere remote in Devon, UK.

Peter wrote:

The subject header asks about “legitimately”.

Well, lots of broken parts in a dedicated and un-named “broken parts cabinet” suddenly start working again for no apparent reason when testing them properly the second time. Nothing illegal about that.

ENVA ENOP ENMO, Norway

LeSving wrote:

Well, lots of broken parts in a dedicated and un-named “broken parts cabinet” suddenly start working again for no apparent reason when testing them properly the second time. Nothing illegal about that.

In fact, MOSFETs have a failure mode that tends to self-restore after a year or two in storage (or faster when stored at elevated temperatures). I observed it myself on an old Toshiba laptop with a blown power controller – after a couple of years on the shelf it started working again.

LKBU (near Prague), Czech Republic

Many thanks wigglyamp.

I cannot see anyone doing any of this other than your last paragraph. However, IME, EASA has lots of ex CAA Level 2 or ex Part 21 people working there and I have not found them at all helpful. I tried this years ago (when I was G-reg) with the approval of a backup oil pressure gauge, made wholly out of TSOd parts incidentally. However it could be that they were not receptive to an approach from a non Part 21 person. (It was a trivial Minor mod on an N-reg).

What would be the legit procedure on an N-reg? I know there are specific FAA concessions (already posted here recently) whereby commercial electronic components can be sourced without paperwork.

More practically speaking, since a company such as this is long gone, and there isn’t any stock of these signal conditioners, most solutions will be either “private repairs” or salvage from parted-out planes. Both routes are going to get scarcer over time (competent people retire and are rarely replaced, and parted out stock obviously declines, respectively) but then the population of the planes using these will decline also (parted out, crashed, scrapped). I wonder if the problem just takes care of itself? This box is used on Cessna twins AFAIK but judging from the crazy price it might also be used on King Airs.

Administrator
Shoreham EGKA, United Kingdom

What would be the legit procedure on an N-reg? I know there are specific FAA concessions (already posted here recently) whereby commercial electronic components can be sourced without paperwork.

There used to be a UK CAA Airworthiness notice that allowed a company to use commercial electronic components without release provided that they came from an organisation holding a recognisable quality approval such as BS5750 or ISO9001. However that’s long gone.

There are fewer ex UK CAA senior staff at EASA and those remaining in GA tend to be the more pragmatic in dealing with awkward issues – it was one such who helped me find a solution to an airframe component problem with a Fuji through an EASA minor repair.

As for how to deal with this on N reg aircraft – unknown to me unfortunately. I do have a friendly DER I can ask if it’s a real issue.

Last Edited by wigglyamp at 25 Mar 19:58
Avionics geek.
Somewhere remote in Devon, UK.

There used to be a UK CAA Airworthiness notice that allowed a company to use commercial electronic components without release provided that they came from an organisation holding a recognisable quality approval such as BS5750 or ISO9001. However that’s long gone.

What does this exactly mean now? Does it mean that e.g. a BC109 transistor used in an autopilot has to be bought from Honeywell/King, with the paperwork obviously? Or does it mean that the transistor has to be bought with a suitable traceability certificate e.g. a CECC (or whatever it is now called) release?

Sourcing via ISO9000 is completely meaningless today except as a pure CYA exercise…

I am deliberately sticking to discussing the legit route The “pragmatic” route is obvious, but you can’t use it if the customer is likely to spill the beans

If you could get a quick input from your DER, that would be great.

Administrator
Shoreham EGKA, United Kingdom

Ultranomad wrote:

In fact, MOSFETs have a failure mode that tends to self-restore after a year or two in storage (or faster when stored at elevated temperatures).

I did something similar with a graphics card for a PC. Searched the web, and found several people had fixed them by putting them in the Owen at 90-100 degrees (as I remember, could be more ) for some hours. It worked, but in my case only temporarily for a week or so.

ENVA ENOP ENMO, Norway
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