27 I have taken that distillation of the authorities as a guide, influenced by the caution expressed by Sheppard J in Wedesweiller at 531 in a passage which preceded that quoted by Wilcox J in Hunter Valley at 349. I have also treated Principle 1 in Wilcox J's exposition as modified by the gloss put on it by a Full Court of the Supreme Court of Victoria in Dix v Crimes Compensation Tribunal [1993] 1 VR 297. That gloss was to the effect that it is not a pre-condition to the exercise of discretion that an applicant show an "acceptable explanation of the delay."
28 Although eighteen months have elapsed between CASA's decision to issue Instruments 130/05 and 131/05 and the making of the present application, the delay has been attributable, in part, to initiatives taken by CASA in an entirely understandable attempt to achieve a regime for the conduct of parachute descents at Barwon Heads aerodrome which had the assent of all interested parties. Part of that initiative was to propose the draft Instruments to which the letter of 6 June 2005, noted at [15] of these reasons, was related. It may be conceded that the applicants' somewhat leisurely prosecution of their proceedings in the AAT contributed to the lapse of over twelve months before CASA requested, in August 2006, a period of six weeks in which to obtain instructions as to whether it would revoke Instrument 130/05. After CASA's unequivocal intimation, on 28 September 2006, that both Instruments 130/05 and 131/05 would remain in force, the applicants proceeded with reasonable expedition to prepare their substantive application in this Court and seek an extension of time within which to lodge it.
29 I do not regard the present case as on all fours with Applicant A2 of 2002 v Minister for Immigration and Multicultural and Indigenous Affairs [2003] FCA 576 where von Doussa J observed, at [9];
' … … I do not think the delay is satisfactorily explained by the fact that the applicant hoped during that time to get a favourable exercise of the Minister's power under s 417. The application under s 417 indicates an acceptance of the decision of the Tribunal, and a decision on the part of the applicant to take another course. Having taken that other course, in my opinion he must live with the consequence of the delay that occurred.'
See also Batuwantudawa, in the matter of an application for Writs of Certiorari and Prohibition against Ruddock (supra) per Gray J, at [9].
30 In the present case, as the history makes clear, the applicants have consistently intended to procure a review by the AAT of the merits of the decision to issue either or both Instruments 130/05 and 131/05. The only time at which they could be taken to have resiled from that intention was while there was a prospect of those Instruments being replaced by versions more favourable to the applicants which had been forwarded under cover of CASA's letter of 6 June 2005. By contrast with Applicant A2 of 2002 and Batuwantudawa, there was no acceptance by the applicants of the validity of the decision to issue either Instrument 130/05 or 131/05.
31 I have also been influenced, in considering the effect of delay on the exercise of the Court's discretion, by the absence of any suggested prejudice flowing from the delay to CASA's ability to defend, under the AD(JR) Act, the decision to issue Instrument 130/05. As I understand it, the challenge to that decision turns entirely on the interpretation of legislative provisions relied on as the source of power to make the Instrument. CASA's case by way of upholding the validity of the Instrument will, therefore, not call in aid any exercise of discretion or other matter on which the recollection of a decision-maker or the existence of contemporaneous records could bear. Consequently, CASA is in as good a position now to resist the substantive application as it would have been had the application been lodged in May 2005.
32 I have not been persuaded that what Wilcox J, in discussing the Principle 4 identified in Hunter Valley, called "public considerations" ought to be allowed much weight in balancing the factors tending for and against an extension of time. It is true that other users of the aerodrome, including Begg, have had the advantage, since April 2005 of the effective prohibition on parachuting brought about by Instruments 130/05 and 131/05. However, there is no evidence that those other users have substantially altered their practices in reliance on the absence of a challenge to either Instrument. The inference which I prefer is that those other users have been aware of the applicants' concern to challenge, in the AAT and elsewhere, the validity of the decision to issue the Instruments and have not been lulled into a false sense of security by the applicants' failure before now to lodge an application under the AD(JR) Act. Moreover, even if the substantive challenge to Instrument 130/05 were to succeed, other users of the aerodrome would largely be protected by the continuance in effect of Instrument 131/05. If that protection were, for some reason, perceived to be inadequate, an appropriate stay or other interim order by this Court, when finally determining the challenge to Instrument 130/05, could remedy the deficiency.
33 I have not been influenced by the partly parallel proceeding between the applicants and Begg which is pending in this Court; see [21] above. That action is listed for trial in December 2006 and will almost certainly be determined, at least at first instance, before the present substantive application against CASA comes on for hearing. Accordingly, if, as has been contended it may, the judgment in the Begg litigation renders academic the issues between the applicants and CASA, account can be taken of that effect without irremediable prejudice to either party.
34 It is inappropriate, I consider, to conduct, at this stage, a detailed examination of the applicants' prospects of success on the substantive application. Such an examination would include an assessment of CASA's invocation of the principles of Anshun estoppel. Whether that principle is available to bar the applicants from relief under the AD(JR) Act or s 39B of the Judiciary Act will depend on a detailed scrutiny of the claims advanced in the applications heard by Selway J, the conduct of the parties to those proceedings and how his Honour chose to resolve the issues which were raised for determination. Similar considerations apply to the contention that the decision to issue Instrument 130/05 was not "a decision of an administrative character" within the meaning of s 3(1) of the AD(JR) Act. On its face it was a decision by a Commonwealth authority under "an enactment" as defined in par (a) or (c) of the definition of that expression in s 3(1) of the AD(JR) Act.
35 It is sufficient, in my view, for the purposes of exercising the present discretion, that the applicants have a reasonable prospect, if the extension be granted, of obtaining the relief which they seek under the AD(JR) Act. The weight to be given to that factor is, if anything, enhanced by the consideration raised by CASA that, absent the claim for relief under the AD(JR) Act, this Court may lack jurisdiction to entertain the applicants' substantive claim because it does not raise a "matter … arising under any laws made by the Parliament" within s 39B(1)(A) of the Judiciary Act. The complexities which may attend the resolution of that issue have been clearly signalled by Branson J in Mirvac Homes (NSW) Pty Limited v Airservices Australia (No 1) [2004] FCA 109. It is sufficient for present purposes to observe that a discretionary extension of time should not be withheld, in the absence of other factors militating against an extension, if an applicant will thereby be put at risk of a complete denial of a resolution on the merits of a controversy which he or she seeks to raise. That is particularly so where, as here, the controversy is as to a question of public law as fundamental as whether an instrument promulgated by a statutory authority like CASA is ultra vires. The weight to be attached to this consideration which has proved decisive in my exercise of the discretion, has been increased by the recollection that, in the events which have happened, a failure by the applicants to obtain a resolution of the question just identified in relation to Instrument 130/05 will indefinitely shut them out from merits review by the AAT of the decision to issue Instrument 131/05.