Aer Rianta has argued before the High Court that the Commissioner for Aviation Regulation relied excessively on the views of airlines and acted in excess of his powers when deciding the maximum level of airport charges to be levied at Dublin, Cork and Shannon airports.

Mr Paul Gallagher SC, with Mr Paul Sreenan SC, for Aer Rianta, said the regulator - Mr William Prasifka - exceeded his powers in making findings on issues regarding capital investment in airports and disallowing certain proposals for capital projects, including a proposed new runway at Dublin Airport, which findings appeared to be based on a report which the regulator had sought from a firm of US consultants, IMG Consultants.

Counsel was making submissions yesterday during the hearing of proceedings taken by Aer Rianta challenging the regulator's decision of August 26th, 2001, specifying maximum charges to be levied by Aer Rianta at Dublin, Cork and Shannon airports.

In this latest stage of the case, which is expected to last four weeks, Mr Justice O'Sullivan is hearing argument on the construction of several pieces of legislation, including the Air Navigation and Transport (Amendment) Act 1998 and the Aviation Regulation Act 2001 providing for the establishment of the Commission. The case highlights tensions between the obligations of Aer Rianta under the 1998 Act and those of the Commission under the 2001 Act.

Aer Rianta contends it has a range of statutory powers under the 1998 Act relating to the operation, management and development of State airports which powers remain unaltered by the 2001 Act and that the regulator, in making his decision on airport charges, has acted in excess of his powers under the 2001 Act.

While the 2001 Act purported to amend certain sections of the 1998 Act, it did not amend in any material way the provisions dealing with duties imposed as a matter of law on Aer Rianta, he said. One of the fundamental difficulties Aer Rianta had with the regulator's approach was that it prevented the company from discharging those statutory duties. Aer Rianta had almost 70 years experience in managing airports.