If I told you that many of my colleagues were Danish & you consulted your list you would find that
This is not the case. Spain has double taxation agreement with every EU country.
is not 100% correct.
Many? I understand this to mean that not everyone was paying taxes. Taxation is not a volunteerly issue.
Have you heard of countries like Andorra perhaps ? there are perfectly legal ways of reducing ones tax burdens.
You are right about this, but this is not the issue I am trying to address. I am addressing the issue pointed out by NTSB that CAA's oversight is made much harder when airlines outsource most of their services.
And also that the legal bonding between the AOC holder and the flight crew member is done by a contract agency of which the CAA has no oversight. And that this contract states that the flight crew member can not disclose this contract to anyone.
Don't really get your point here. If Contractors are subject to the same recruitment/selection/training/testing/disciplinary standards, which part of our operational performance is not under the company & local CAA's oversight . Not disclosing your contract is a Red Herring. .the contract is a commercial agreement between you and your agency , which will contain no clause asking you to disregard/exceed what is stipulated in your Ops manual. . .so, don't really see your point here. Tell me anyhow, what interest have for example the IAA shown in Ryanair trampling all over & changing at will the pilots (permanent as well as Contractors) T's & C's over the years . Not a lot that I saw.
I think you are trying to make something out of nothing & I would suggest Ryanair for example (now 70% contractors
AFAIK) has never had a problem with "supervision or control" of its workforce.