How do we think all these old Supermarine Spitfires and Mustangs keep flying? Or any aircraft that’s orphaned? It’s a grey zone. The less they know, they better.
AdamFrisch wrote:
How do we think all these old Supermarine Spitfires and Mustangs keep flying? Or any aircraft that’s orphaned? It’s a grey zone
You’re confused: The OP was for a Certified Aircraft. Those WWII planes are all in experimental or similar categories. Besides, the point was the fake sticker – not the use of the suitable part.
One notable factor, I recall from speaking to somebody in the vintage business, is that the drawings for say a Spitfire do all still exist. So you can fabricate a part IAW the original data. That is what keeps Spitfires in the air; at a massive cost but legally.
The problem with owner produced parts is that in most certified aircraft scenarios there are no drawings (that you can get) or any other design data available. You can do sheet metal repairs IAW AC 14-43 or whatever it is called (a generic FAA repair manual, mostly applicable to unpressurised hulls) but you could not machine up your own retractable landing gear legs – even if you (obviously) can reverse engineer the dimensions, you won’t have the metal details unless you spent a whole lot more on metallurgical testing (and a DER).
Peter wrote:
but you could not machine up your own retractable landing gear legs – even if you (obviously) can reverse engineer the dimensions, you won’t have the metal details unless you spent a whole lot more on metallurgical testing (and a DER).
Under EASA this is possible, when you design a new part. I actually know of some aircraft for which new parts have been designed and approved as the orginal parts weren’t up to job and limited available.
Peter wrote:
And the actual manufacture of a certified product can be anywhere. The King autopilot servo PCBs are made in Indonesia – a truly bizzare practice given that they cost about $10 to make, and the servo lists at $4000.
This again is a different kind of product, this is an TSO part, which requires other design and production approvals then for PMA parts. The PMA approval is basically a design and production approval in one, which is very usefull for less expensive parts. Full certification would drive up the cost a lot.
For most issues a change can be designed. Another example is for wings with life limited. There are (under EASA) programms for certain wings to give them additional inspections to extend the life limit of the part. There are also modifications available (improvement), to get rid of this inspections and the life time limit.
For example, with the limited support for dual magneto’s, there will always be an alternative (which might cost money) to keep flying. Either another company manufacturers more PMA parts then they do know, so you can keep overhauling it, or someone will design an extensive modification, as you allready posted.
Rules cannot be written for every scenario in life. I think the grey area here should be (and in practice is) construed with a bit of common sense by both the licensing as well as accident investigating authorities (and ultimately, courts, too). To me, two scenarios can occur in practice: (a) owner-maintenance and part manufacturing; since we all can be presumed laymen, only stuff clearly permitted by the EASA/FAA rules and the maintenance manual can be done; (b) licensed maintenance shop – I think they should not be considered equal with us, laymen, when it comes to privileges of navigating in the grey zones (and I don’t mean to start a discussion of varying service quality here); their licensing requirements are quite high and with those requirements, arguably, some authority to judge acceptability of such parts as relays should be coming (why else should a mechanic have all that experience and training, if everything was written in the rules/books/manuals); if they can show that they exercised due care and did not breach any clear rule, they can’t be held liable for breach if they install an “OEM servo”. If you as owner say to any authority (should they ask) that a professional third party installed the part, you cannot be held liable either. Maybe using a properly licensed shop could be kind of way out of the grey TSO/PMA zone / as long as they are willing to use the “OEM part”. In my (limited) experience, the licensing authorities (FAA/EASA) have other things on their agenda than chasing pilots/owners/maintenance shops for what is installed in their aircraft / as long as it is SAFE and the basic paperwork is fine.
