ATLANTA ( TheStreet) -- Delta ( DAL - Get Report) made it a clean sweep in the union election process, winning its third major victory Tuesday as customer service workers voted not to unionize.

Of 12,518 votes cast, about 69% voted against representation by the International Association of Machinists. About 80% of 15,436 eligible voters turned out.
Delta

"There is no better testament to how well the direct relationship works at Delta than the fact that the results of these post-merger elections -- even with the voting rules changed in the middle of the process -- have been the same," Delta said in a prepared statement. "Delta employees want to preserve the special Delta relationship."

The IAM, however, said in a prepared statement that "Delta Air Lines' continued illegal interference in union elections has once again denied employees their legal right to elections free from intimidation." The union said that by Thursday, it will present the National Mediation Board with evidence of interference in the fleet service election. Soon afterwards, it will file charges of interference in the passenger service election.

The NMB found that Delta interfered in an election for flight simulator technicians this year and in a 2000 election for fleet service workers, the IAM said.

The pattern in the three elections has been the same. The unions lost by ever increasing margins -- staring at just 2% -- and then said they would appeal the results, arguing that Delta interfered with the election process by taking advantage of its ability to force information on employees in the workplace.

Delta has said that it did nothing wrong and wants to move on with the process of integrating workers from Delta, which has not generally been unionized, with unionized former Northwest workers, following the 2008 merger.

In October, 51% of flight attendants voted against representation by the Association of Flight Attendants. In November, 52% of fleet service workers voted against representation by the IAM.

-- Written by Ted Reed in Charlotte, N.C.

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