CHARLOTTE, N.C. ( TheStreet) -- Despite widespread hopes that a merger with American ( AAMRQ.PK) would bring closure to a pilot seniority dispute at US Airways ( LCC), it's not that simple.

A controversial 2007 seniority ruling by arbitrator George Nicolau followed the 2005 merger between US Airways and America West. The ruling, which resulted from binding arbitration, led to a bitter separation among pilots from the two airlines.

This month's American/US Airways merger will lead to another round of pilot seniority integration, this time under guidelines established by the McCaskill-Bond Amendment. The 2007 congressional legislation requires unions to resolve seniority disputes through negotiations and, if that doesn't work, through binding arbitration. Leaders of the Allied Pilots Association and the U.S. Airline Pilots Association seem hopeful that the process will go smoothly and resolve the simmering dispute at US Airways.

But another round of binding arbitration, if it is not based on the Nicolau list, isn't acceptable to former America West pilots. Their attorney said they will go to court if the ruling isn't part of the merged airlines' seniority list.

"We expect the parties to abide by the Nicolau list, which is the arbitrated joint seniority list accepted by the company in 2007," said Mark Burman, spokesman for Leonidas, a group of pilots who have supported the continuing court battle to have the ruling implemented.

On Feb. 7, US Airways pilots overwhelmingly approved a memorandum of understanding, setting temporary contract terms that would be implemented in the event of a merger. In a Feb. 18 letter to the labor attorneys for US Airways, Leonidas attorney Marty Harper referred to a 2010 finding by the Ninth Circuit Court of Appeals that the west pilots' claims regarding Nicolau implementation would be "ripe," or ready for a court's consideration, once a contract was signed.

"The time has come with ratification of the MOU and approval of the merger," Harper wrote.

Harper said west pilots have until early August to seek relief in their duty of fair representation case against USAPA. "They will do so, " seeking a temporary restraining order, if pilots have not agreed prior to that date to implement the Nicolau award, he said.

USAPA President Gary Hummel has said the west pilots are trying to delay the merger. But Harper wrote that "the west pilots supported this merger from the start, have no interest in delaying it now. (But) the west pilots must do whatever is needed to defend the Nicolau award."

In a Feb. 21 letter to USAPA members, Hummel declared the union continues to oppose the Nicolau ruling.

"This merger provides substantial and life changing benefits to all USAPA pilots, including those based in Phoenix," Hummel wrote. "USAPA will aggressively oppose any efforts to slow down or stop the merger process and will be equally vigilant in adhering to our constitutionally mandated principles that reject the Nicolau Award in its entirety."

In his letter, Hummel said USAPA has asked the Ninth Circuit for an expedited ruling on a pending appeal filed by US Airways. The airline, joined by west pilots, appealed an October ruling by U.S. District Court Judge Roslyn Silver in its case seeking clarification of the necessity to adapt the Nicolau list. In her ruling, Silver said USAPA's seniority proposal could be acceptable "provided it is supported by a legitimate union purpose."

USAPA wants an expedited ruling because "We want there to be no uncertainty about whether USAPA can pursue a different seniority proposal," Hummel said.

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

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