as to the financial situation at Van’s right now, I found this video nicely factual and balanced:
Is there any heat treatment which could be used to stress-relieve the dimpled holes, so the cracks don’t propagate?
I am thinking of localised inductive heating of the rivet and the immediately adjacent material.
Peter wrote:
any heat treatment which could be used to stress-relieve the dimpled holes, so the cracks don’t propagate?
Maybe, but not that I know of 
If a crack forms (again, not talking about a new build with pre-existing cracks that formed during the building process), the only “repair” process is stop drilling the crack. Its progress can then be monitored, or a repair such as replacement, doubler, or reinforcement modification, performed. The FAA details most of the ways to deal with cracks in it’s AC 43.13-1B document, which purpose is stated as (excerpt):
This advisory circular (AC) contains methods, techniques, and practices acceptable to the Administrator for the inspection and repair of nonpressurized areas of civil aircraft, only when there are no manufacturer repair or maintenance instructions. This data generally pertains to minor repairs.
@Peter, the annealing cycle for 2024 AL is about 400 degrees Celsius for 2 hours, followed by slow cooling. And you’d meanwhile need to maintain the strength of the heat treated alloy in some of the adjacent material, by not heating it, which would be impossible for that length of time.
I had a similar situation doing shrink fits of steel components into aluminum housings, the issue being that the temperature required to expand the housing enough for a tight shrink fit was high enough to age the material to a higher temper in 30 minutes or less. I suggested we buy material in a lower temper and accept the aging. The idea was shot down… too imprecise with the oven on hand, no material certificate of conformance would apply etc. Also stress corrosion cracking issues apparently existed with some tempers and not with others etc etc. We could have done it for an Experimental application though.
Are their financial statements published somewhere?
So, apparently the FAA has sent a letter to all DARs regarding VAN’S laser cut parts. It doesn’t appear to give specific guidance but does say, “It is recommended that when certificating potentially affected aircraft, an assessment is made as to whether there are any affected parts in the build.”
Like I was fearing this seams to already becoming a bigger issue. Just adding another unknown to a list of unknowns.
What function could a DAR have on an EXP category aircraft?
On a certified, this would be massive.
Peter wrote:
What function could a DAR have on an EXP category aircraft?
On a certified, this would be massive.
They can deny an airworthiness certificate for any reason they feel the aircraft is “unsafe”.
RV8Bob wrote:
apparently the FAA has sent a letter to all DARs regarding VAN’S laser cut parts
Same direction on the old continent. Learned yesterday that our NAA (FOCA) has been informed about the issue. I guess the same will happen in the different European authorities exercising positive control on the PtF issuance of homebuilts.
What function could a DAR have on an EXP category aircraft?
It’s interesting to consider. FAA DARs do not inspect or approve the design of an E-AB plane prior to issuing an airworthiness certificate, but they do inspect for basic workmanship and have authority on that limited level. 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, which is just an uncertified parts supplier to the E-AB builder who has a direct 1:1 relationship with FAA.
