Unite is to go to the High Court today over changes brought in by British Airways (BA) to cabin crew last year.
The union claims it was not consulted properly on the changes, which included a pay freeze and reduction in cabin crew on long-haul flights.
The changes were made by BA to cut costs.
The union had been set to strike over the concerns at Christmas, but a High Court action by the airline prevented it.
A new strike ballot will close on February 22.
On Friday the airline is expected to reveal a considerable loss for the last quarter of the year from October to December.
The airline suffered a loss of £292m for the six months to the end of September 2009.