British Airways cabin crew are to strike for three days after talks broke down between the airline and the union.
BA flights were badly disrupted last month by severe fog
The crew will stage industrial action between 29 and 31 January over sick leave, pay and staffing issues.
The T&G union said if there was no further resolution two more three-day strikes would happen in February.
BA said it was "extremely disappointed" by the news. It will let people booked to fly between 29 January and 16 February change the date of their trip.
'Chaos' for passengers
Cabin crew have complained that a new regime on sickness pay, introduced 18 months ago, mean they are forced to work when they are ill.
BA insisted it was merely cutting high levels of sickness absence. The average of 22 days had been reduced to 12 but this was still above the UK average of seven per worker per year, it said.
The union held several meetings with BA bosses last week following a 96% vote for industrial action by the 11,000 cabin crew workers.
Jack Dromey, T&G deputy general secretary, said British Airways management had "completely failed to engage" with the union.
"Our members are fed up with being bullied into coming to work when sick, and with the divisions caused by poverty levels of new entrant pay scales," he said.
The union said it was ready to resume talks at any time, but BA said the union was refusing to talk to the airline.
BA said it had made "serious proposals" to change the way the sickness policy was applied. And it said the union was now demanding a "significant" pay rise, whereas it needed to remain competitive.
Chief executive Willie Walsh said the strike would cause "chaos" for hundreds of thousands of customers.
It would also cause further damage to the airline, which has been hit in recent months by security and weather problems.
In December, domestic BA flights from Heathrow were cancelled for three days because of fog - a move that could cost the airline as much as £15m.
As well as delayed flights, there was further bad publicity as a backlog of more than 10,000 bags checked in by BA passengers piled up at the airport.
Meanwhile in September, BA said August's terror alerts cost it £40m as the airline was forced to cancel of more than 1,000 flights.