All unions at TEAM, the Aer Lingus aircraft maintenance subsidiary, are expected tomorrow to enter negotiations together for the first time. The move is a breakthrough as efforts continue to reach agreement on selling the company to FLS Aerospace, the Danish-based group.

Craft unions are meeting in Dublin tonight to decide whether to enter the negotiations. It follows an exchange of letters at the weekend in which the Amalgamated Electrical and Engineering Union (AEEU) solicitor received clarification that the letters of guarantee held by its members were being recognised by Aer Lingus.

AEEU area secretary Mr Mick Brennan said last night that the letter gave the guarantees his members were seeking on a range of issues, including pension benefits and travel concessions. Around 200 AEEU members are taking legal action over the letters of guarantee and other issues. The letters of guarantee have featured strongly in all talks at the TEAM subsidiary. The letters entitle 1,200 of the 1,600 workforce to return to Aer Lingus with their service, pensions and other entitlements intact. It is understood that the initial offer from Aer Lingus of £28 million to buy out the letters will be considerably enhanced. Details of the improved package should emerge at tomorrow's meeting. If agreement is reached the legal proceedings on the letters should be dropped.

The craft unions were supporting the AEEU stance and had not entered talks which began last month. It meant that about two-thirds of the workforce were not being represented at the talks.

Earlier this month Mr Gerard Durcan, a senior counsel, was appointed as a facilitator to broker the talks. Sources close to the talks said last night that his appointment had helped to speed up the process and a number of issues were near resolution. Ultimately, whatever is agreed at the table will have to be put to individual TEAM employees as they hold the letters of guarantee.

Resolving these issues is crucial to the sale of the facility. FLS Aerospace is currently carrying out a due diligence process on TEAM which is expected to be completed by the end of this month.

FLS Aerospace is expected to bid in excess of £25 million for TEAM.