Unionized pilots of South Korea's No. 1 flag carrier Korean Air Lines Co. said Monday they will launch a 12-day strike later this month. 

The pilot union said it notified the company that its union members will lay down their tools from Dec. 20 to 31. They are likely to carry out the plan if the union and the management fail to reach an agreement on wage deals at their final negotiation session scheduled on Wednesday. 

A majority of unionized pilots of Korean Air already voted "yes" to go on strike in February, demanding a salary hike and better working conditions following a failure to iron out differences in opinions. 

Pilots are seeking a 37 percent hike in wages for themselves, while the company proposed a 1.9 percent increase, which it said is in line with the wage growth rate for other non-pilot workers.

"For the last 290 days, we've met with the management to reach an agreement, but the management is just forcing the union to back down without making any changes from their original stance," the union said. "The management has been also putting our members at a disadvantage and meting out penalties to the union executives." 

The government designated the airline industry as "critical" to the public, making it almost impossible for pilots to go on a full strike. Even if they do so, the pilot union must maintain at least 80 percent of international flight operations to minimize disruptions. For domestic routes, 50 percent of pilots should remain at work, but flights connecting Jeju Island must be at least

70 percent in operation. 

The union said the pilots of B737 aircraft will not join the strike in order to minimize possible disruption on domestic flights at the end of the year. 

The management said the company will try its best to solve the wage issues through dialogue. 

"It seems that the union announced its strike plan as a way to put pressure on the management ahead of the negotiation session on Wednesday," a Korean Air official said. "The company will be prepared for our customers to avoid any inconveniences through the possible strike."

Korean Air pilots have been complaining about their relatively low salaries compared to those of foreign airlines, a gap they cite as the main reason for many of their coworkers leaving for higher-paid jobs, mostly in China. 

However, they have drawn criticism for demanding more at a time when they are already much better paid than other workers and for holding public transportation hostage for their own interests.

(Yonhap)