By Andrew Chung
(Reuters) - A group of 13 flight attendants say they were illegally fired by United Airlines after refusing to fly on a Hong Kong-bound plane last July that had a "threatening" message scrawled under its tail engine, according to a complaint filed with the U.S. Department of Labor.
In the complaint, filed Tuesday, they said the words "Bye Bye" and two faces, one smiling and the other with an expression that the workers described as "devilish," were found finger-drawn in oil grime under the auxiliary engine of the plane at San Francisco International Airport.
The flight attendants said the airline refused to deplane the passengers and conduct a security inspection. They said they disobeyed orders to work, believing the lives of more than 300 passengers and crew on the jumbo jet could be endangered.
United accused the flight attendants of insubordination and fired them all, according to the complaint.
United, a unit of United Continental Holdings Inc, said it would fight the pending litigation vigorously. A spokesman told Reuters in an email that the airline's teams had investigated the issue and found there was no "credible security threat."
The airline followed all of the Federal Aviation Administration's procedures, the spokesman said, noting that the pilots and mechanics had deemed the plane safe to fly.
(Reporting by Andrew Chung; Editing by Ted Botha and Leslie Adler)