Nearly 500 pilots at Aer Lingus are to stage a 48-hour strike next Tuesday and Wednesday in protest at what they said were moves by the airline to employ pilots at its new base in Belfast on less favourable terms and conditions than those applying to staff in Dublin.
The pilots, who are members of the Irish Airline Pilots' Association (Ialpa) branch of the trade union Impact, are understood to be considering further industrial action if the dispute is not resolved.
Impact said last night it had been informed by the company that it did not intend to honour existing collective agreements for new pilots to be based in Belfast.
Assistant general secretary of the union Michael Landers said it had been informed by the airline that the new pilots would not be given access to the company pension scheme. Impact also believed that the basic pay on offer in Belfast would be lower than the existing rate for pilots.
Mr Landers said collective agreements currently in place, which the company did not intend to honour for the Belfast base, covered issues such as days off and rest period between flying duties.
The planned strike next week was covered by a ballot held in June which allowed for industrial action in the event of the company seeking unilaterally to change pilots' pay and conditions, he added.
In a strong reaction last night, Aer Lingus said it was "angry and disappointed that pilots would choose to attack customers in an act of self-centred brinkmanship".
A spokesman said the recruitment of new staff at local rates had always been a fundamental element of the plan to establish new bases outside the Republic of Ireland.
The airline also warned that passengers were likely to face disruption to services next week and said management was working on alternative arrangements and contingencies.
Advertisements for pilots to be based in Belfast were placed on the Aer Lingus website yesterday. They did not set out the terms and conditions on offer.
Speaking after a meeting of pilots at Dublin airport last night, Ialpa president Capt Evan Cullen said the move by Aer Lingus was a flagrant breach of its collective agreements and of solemn commitments made by the airline to its employees in advance of last year's stock market flotation.
"We are not going to allow Aer Lingus treat its Belfast-based pilots as second-class citizens who can be paid less and treated worse than their colleagues in Dublin.
"Aer Lingus has freely entered into collective agreements that cover all pilots employed by the airline and we just want the company to honour its commitments," he said.
Aer Lingus said it had been in negotiations with pilots for some time on a range of efficiencies that were essential to maintain the competitiveness of the business.
"Earlier this year both the Labour Court and the related Flynn report recommended that the company be allowed open new bases outside the Republic of Ireland on local pay and conditions.
"In calling this strike action, the pilots are directly ignoring those recommendations. This cynical attempt to use a new base as a veto on essential progress towards competitiveness is unacceptable and is deeply regrettable given the need to grow the company as an independent force in the market," the airline said.
It advised customers seeking information about the impact of the dispute to call 0818-365044. "Aer Lingus will offer free change of flight details or a free refund for customers should they desire it," the airline said.
The biggest trade union in Northern Ireland, Unite, also responded angrily to Aer Lingus's plans. The union's regional secretary for Ireland, Jimmy Kelly, said it would not tolerate Aer Lingus "parachuting into Belfast" and using workers' wages and conditions in the drive to push down costs.
