Capot, thanks. Yes, it is obviously a shameless freebee but am trying to find an excuse to make it not possible without then having life made too difficult back in Nigeria. We do not have a European office or address, so we cannot issue a letter of invitation for the Schengen visa. The NCAA's retort is that the maintenance facility will have to provide a letter of invitation. The maintenance facility are, of course, not keen to do this because they do not want to take responsibility for him, nor do they particularly want him on their premises anyway. Does the maintenance facility have any obligation to provide an invitation?
The solution I am hoping for is that the correct protocol is that the NCAA has to write to DGAC to request permission to visit the facility. If the permission to visit is granted, then the facility can issue a letter of invitation for the visa. If I can find that in writing, then I know the NCAA will quietly drop the subject, because they will not want to write a letter to DGAC.