The High Court has found that Aer Lingus was in contempt of court when it sent certain solicitors' letters to a number of workers who had returned to the company after working with its aircraft maintenance subsidiary, TEAM Aer Lingus.
The workers had alleged the letters threatened them with redundancy.
Some 56 workers claimed the company had improperly sought to influence and interfere with them by imposing on them its own interpretation of legal proceedings last year, and of the judgments on those proceedings.
Last October, Mr Justice Kearns held that aircraft engineers who returned to work with Aer Lingus in 1998 after working for a period with TEAM Aer Lingus were entitled to be paid at the same level as engineers who did not go to TEAM.
In his ruling, Mr Justice Kearns held that the claimants were entitled to be treated as if they had never transferred to TEAM.
He found they were entitled to all appropriate increments or benefits on the basis that they had earned and achieved the same seniority by 1998 as those Aer Lingus employees who did not transfer.
The workers subsequently claimed that letters sent to them last December by Aer Lingus solicitors which, they alleged, threatened them with redundancy, and further letters sent last month, placed Aer Lingus in contempt of the court's decision.
Mr Justice Kearns found the letters unwarranted and improper. He said he did not intend imposing any fine on the company but added that the letters should be withdrawn.