(Reuters) - Southwest Airlines ( LUV ) was ordered by a federal appeals court on Monday to face a lawsuit by its pilots union, which accused the carrier of violating federal law by intimidating and disciplining pilots for affiliating with it.

The 5th U.S. Circuit Court of Appeals said the union sufficiently pleaded that Southwest ( LUV ) had anti-union animus, triggering an exception that would allow the lawsuit to proceed rather than send the dispute into arbitration.

It reversed a lower court judge who said the dispute should be arbitrated.