The operators of Dublin Airport have been issued with fresh warning letters from Fingal County Council following new complaints relating to its north runway.
There is mounting pressure on council officials to complete an investigation into ongoing complaints by local residents.
A separate review of noise levels and their effects on local communities has also been initiated by the Aircraft Noise Competent Authority (Anca), a separate and independent directorate within Fingal County Council.
Residents across north Co Dublin are continuing to challenge the new runway, which opened last August, after many found themselves unexpectedly affected by aircraft noise.
According to many in the surrounding communities, efforts to amend flight paths last month have made little difference, rendering some areas quieter but some noisier.
Accusations the airport is in breach of planning conditions for the runway have been rejected by DAA, the company that runs the airport. It has been under investigation for alleged noncompliance since last year.
It has now emerged two further warning letters were issued by Fingal County Council following continued complaints.
A report circulated to local representatives noted that technical responses to its initial letter had been received from DAA and were under review “as part of its ongoing investigation into an allegation of unauthorised development”.
However, remarking on the time it was taking to arrive at a planning decision at Monday night’s council meeting, Independent Cllr Cathal Boland said completing its obligations in a “timely manner” was important to the credibility of the local authority and that “external” experts should be brought in to assist if required.
Other councillors questioned how the planning enforcement process was being handled and how long it was taking.
Fingal’s chief executive, Ann Marie Farrelly, said there was a need to safeguard the process by not offering too much detail relating to the ongoing investigation.
She said she had sought a meeting senior management at DAA and said external experts were available to planning officials “where they are needed”, as is external legal advice.
Speaking later, Cllr Boland said this reference to external expertise to help examine DAA data supplied for the investigation was a “very significant development” in accelerating the process.
“The future of how the airport develops will hinge on this,” he told The Irish Times.
A report prepared by Matthew McAleese, Fingal’s director of services for planning, said they are awaiting a response following further warning letters issued at the beginning of March.
Meanwhile, a separate review is under way by Anca evaluating the impact of aircraft noise on the surrounding communities.
DAA has been directed to provide it with operational data on a phased basis until the end of March. Anca is also engaging with DAA on a “significant expansion” of noise-measuring systems in the area.
In a statement, airport management rejected claims it is in breach of planning permission granted for the north runway and said a review undertaken of flight paths had led to amendments last month.
“DAA is aware that Fingal County Council is currently undertaking an investigation into the North Runway planning permission and is fully participating and engaging in this process,” a spokesman said.
“In the meantime, DAA continues to work closely with the local community regarding any issues they are facing as a result of operations at Dublin Airport.”
The spokesman said it was not appropriate to further discuss “matters which are the subject of ongoing statutory planning enforcement and appeals processes”.
An Bord Pleanála is due to issue a decision relating to an expansion of runway use in the coming months.