@Silvaire wrote:
My guess would be that compliance with the Vans memo on the subject would satisfy a DAR, even while understanding that individual aircraft and individual builders have no official relationship with Vans
Everything you wrote is correct. There is also no direct connection between Van’s and the FAA. The engineering assessment is written directly to the builders, not the FAA. Let’s be honest the FAA would NEVER accept that engineering assessment for a certified aircraft.
So, right now, this memo is all the FAA can legally do. Write a letter to the DARs saying laser cut parts MAY pose a risk to safety. I guess it will be up to the individual DAR to determine which is more reliable, FAA ACs, or Van’s engineering assessment.
DARs do not assess engineering, that would be the job of a DER if the aircraft were certified, and the builder for E-AB. The authority of a DAR to defer issuance of an E-AB airworthiness certificate is limited to his assessment of workmanship issues. Where this issue might stand in relation to workmanship versus engineering is an interesting issue, but my guess is that a DAR would not to attempt to override any specific and knowledgeable engineering assessment for an E-AB aircraft.
my guess is that a DAR would not to attempt to override any specific and knowledgeable engineering assessment for an E-AB aircraft
Even with visible cracks on LCP parts? I seriously hope not, engineering assessment or not…
There are effectively 2 problems here: LCPs, which might be dimpled but no cracks and… LCPs which have been dimpled and display visible cracks.
A DAR signing off a certificate with known visible cracks on a new build would set a historical precedent in aviation history.
I’m not familiar with specifically how the Vans memo addresses ‘known visible cracks’ on secondary structure but repeating myself for third time I do not believe an FAA DAR is authorized to or would attempt attempt to override any specific and knowledgeable engineering assessment for an E-AB aircraft. They are called Experimental for a reason.
I’ve heard that when an FAA inspector comes to give the “pink slip” they do not do any inspection at all, but only care if the paperwork is done correctly. They don’t even want to look at the aircraft beyond the basics like the N number, registration holder visible, Experimental sticker, etc. The way it was said to me was “if your paperwork is in order, you can build a door, claim it’s an Experimental aircraft, and we’ll sign it off.”
In a way it makes sense, since if they get into the business of inspecting Experimental aircraft for airworthiness, if something goes wrong, they might share some of the responsibility. If they make it clear that they are only inspecting paperwork, then they are off the hook. As I often say, generalizations are always wrong, so there are most likely some FAA inspectors that will look at an aircraft and refuse to sign off on it if they feel something is wrong.
One of the selling points of using a DAR in the US is that they will include an inspection of the aircraft when they do the paperwork.
Obviously this whole “homebuilt” inspection process is very different in Europe, and much more rigorous.
this whole “homebuilt” inspection process is very different in Europe, and much more rigorous.
The difference is in the intent of the inspection, and the intended government role.
FAA DARs typically start life as A&P mechanics. Their role is not to assess aircraft design, it is to make sure that the aircraft has complied with the FAA requirements for testing an experimental aircraft and to put in place a mandatory test program that protects the public from the potential negative outcomes of the experimental program. The DAR is not ‘on the hook’ for the safety of the design itself, and there is no ambiguity in that regard. However an inspection of workmanship is within their role, more or less at the level of an A&P mechanic.
The definition of an experment in engineering is a real world test of an unvalidated design. That’s what experimental aircraft are by FAA regulatory intent, and individuals in the US are by regulatory intent free to conduct experimental programs on aircraft of their own design, without design approval by anybody. Each individual E-AB aircraft is for regulatory purposes considered to be an unproven individual design created by the builder. For amateur built experimental aircraft specifically the FAA intent also includes recreation and education but there is no intent to limit the risks taken by willing participants of an experimental aircraft program who follow a structured FAA DAR specified test program to protect the public.
and much more rigorous
Also tends to be under-resourced, and dominated by “big personalities” which have been popping up around the scene for the previous 40 years and who therefore always know best, and are answerable to nobody, with the UK LAA being a prime example, but others have not been much better with e.g. the French DGAC demanding design data which most US kit suppliers would never deliver (the post-1998 case etc). What some of these “authorities” will make of the RV dimpled rivet issue, who knows??
The DGAC don’t demand design data. And it is OSAC not the DGAC itself that deals with all these things.
What OSAC want are the plans and to know that you have built to those plans.
RVs are not experimentals in France unless the plans have been diverted from.
Here too you could build a door and fly it under experimental rules. However, you do have to show that it can fly and fly safely with no danger to 3rd parties.
Once all flight tests etc are done under the F-W registration and all the paperwork (dossier) is in and approved you will no longer be F-W but F-P.
After that the dossier is used for the certificates of airworthiness. Any changes to the design or additions during the validity of the certificate of airworthiness need to be added to the dossier. If the changes could affect the control or flight of the aircraft or its safety OSAC will require further tests and when successfully completed these will be added to the dossier and at the CDNR will be issued.
This dossier which also includes a record of the build is then used as the basis for owner/builder maintenance. So buying a French experimental and continuing to keep it on the French register and doing owner maintenance is not a problem and the CDN (again providing no changes are made is issued mainly as a paperwork exercise)
This is outside of any regulat tests necessary for items like radios, transponders or whatever which is basically outside OSACs remit.
With kit built it is a different matter. There is an acceptance that the design and kit is homologated (I think that’s the word we use for something that meets certain standards). So it comes to a degree already tested to a point. There still needs to be a record of the build and flight tests need to be carried out before the aircraft is given its certificate of airworthiness CNSK. Again the presence of a build dossier allows an owner to do their own maintenance because the build record is also the maintenance record. LCPs instead of punched parts might well sound warning bells at OSAC. If VANs have done succesful stress tests etc and added it to their dossier as no safety problem and if this is agreed the parts become homologated and there is no problem.
On the other hand if in the build record, there are signs of cracks round a hole that would set up another alert at OSAC.
They might well insist on further tests being carried out to demonstrate the safety of those cracks. They might even decide that all the tests necessary to go from experimental to F-P are done.
Writing this makes it seem much more complex than it is.
Basically a VANs kit with proper documentation should be automatically accepted (providing the paperwork is in order and that no anomalies are recorded) onto the CNSK as a F-P.
However, in this case there have been changes (LCP holes) and therefore it is up to VANs to demonstrate that these changes do not affect the structural integrity of the aircraft.
If that is done it is up to the builder to demonstrate that he has put the kit together in the planned manner. But if there are cracks and the cracks are not part of the design, well the build is not homologated unless the builder and or VANs can demonstrate that these cracks do not affect safety.
Peter what are you referring to here? I’ve read it and I’ve read the appropriate regulations on the government site.
So I genuinely don’t understand what you are contesting in my previous post.
AIUI an RV kit and design is homologated in France but if the kit is different in some way then it will have to be re-homologated (if there is such a word).
I don’t know about Glasair or Lancair but Velocity and other US kits are.
