Yes there are many reasons for HFDU. One is that the issue is a technical change that is out of scope for an erratum, but does need to be addressed when an updating or replacing RFC is published. It is assumed that the change is not urgent when HFDU is used,There is another that is closer to your point in that the erratum problem is valid, but would take significant work to address, and the base document itself is obsolete so no harm is done in leaving the issue on file. So long as we have technical experts as ADs and not career specialist managers, the system we have with the significant degree of discretion that we impart to the ADs and associated errata classifications works acceptably well in my view. If a fix to an erratum is incorrect it can always be replaced, a second erratum created or an updating RFC published. We should continue to use the pragmatic and reasonably flexible process that exists and seems to work, rather than try to design a fixed “perfect” approach. - Stewart |