Boeing and the International Association of Machinists and Aerospace Workers (IAM) have reached a tentative agreement on a new contract that could end a more than 50-day-long strike that has halted aircraft production.

IAM says in a statement that the tentative contract agreement "will provide job security for its members and limit the amount of work outside vendors can perform in the workplace".

It says the deal is for a four-year accord and it was negotiated over a five-day period with the assistance of federal mediators. A ratification vote is due to be held over the next 3-5 days and if approved it will lead to aircraft production re-starting.

Production has been halted since the strike began on 6 September.

"After 52 days of striking, we have gained important and substantial improvements over the company’s last, best and final offer that was rejected on September 3rd," says IAM District 751 president Tom Wroblewski.

IAM adds in its statement: "Job security and the use of vendors were key issues in the strike that began on Sept 6 2008. Among the other issues resolved in the latest round of bargaining were wage rates, health care benefits for current and future employees, pension improvements and work rule changes designed to improve productivity."

It says full details of the agreement are being withheld until they are distributed to IAM members.