First we must ask what the applicant means when he says "the absolute head of power". I do not know what his intention is when he says "absolute" but I think that the real question that the applicant is asking is "By what constitutional authority does the agency make the regulation." For the Commonwealth of Australia, most of the power of the parliament is given by section 51 ("Legislative powers of the Parliament") in Part V of the Constitution of Australia. The applicant probably wants to know which of the subsections of s 51 gives the authority to make the regulation. The subsections are sometimes called "heads of power".

Now, in my opinion, even if the applicant pays the fee that the agency has estimated, he will be disappointed because of two possibilities. One possibility is that there is no document in the agency to show what the head of power is. In this case, the request will be refused under s 24A ("Requests may be refused if documents cannot be found, do not exist or have not been received"). Another possibility is that the agency has asked an expert before making the regulation. In this possibility, the agency will have asked for legal advice and the advice will be contained in an execmpt document. Section 42(1) of the Act says "A document is an exempt document if it is of such a nature that it would be privileged from production in legal proceedings on the ground of legal professional privilege." This does not prevent the agency from releasing the document if they wanted to, but they will not want to and they will claim the exemption.

In Aviation, a Head-of-Power is that which is referred by the Civil Aviation Act. As you rightly point out, the HOP could go back to the Legislative Powers legislation. That could be the case, but with all aviation related matters, there was a refused change to the constitution in the 1930's, which was over-ridden by the High Court.

We will see what transpires.

Thank you for your note, Mr Cummings. I shall be reading the Civil Aviation Act!