DynCorp International [DI] on Wednesday said a federal appeals tribunal has ruled in its favor over a five-year old contract dispute with the Air Force related to undercharging for maintenance services on trainer aircraft due to erroneous data provided by the government.

The decision to reform the contract for T-6 aircraft maintenance services was made by the Armed Services Board of Contract Appeals (ASBCA) on Aug. 1 and announced by DynCorp on Wednesday

. The ASBCA didn’t award DynCorp financial relief but said in its decision that “the appeal is returned to the parties for a determination of quantum consistent with this decision.”

DynCorp in 2012 won the potential $432 million Contractor Operated and Maintained Base Supply contract for support services for T-6A and T-6B aircraft at several Air Force and Navy locations in the U.S. The incumbent contractor at the time was the former Vertex unit of L3 Communications, which is now L3Harris Technologies [LHX].

During performance of the contract, DynCorp was losing money, and then discovered that some of the data it and its competitors had been supplied by the government on cost per flight hour was erroneous. The data had been prepared by L3 Vertex during the time it had the contract.

The appeals board, which is an independent forum within the federal government that hears and decides on post-award contract disputes between contractors and the Defense Department, NASA and CIA, said that neither DynCorp nor the government would have known that the about the error in the data provided by L3 Vertex.

Therefore, the board said the “just solution is to allocate that risk to the relatively more culpable party best placed to mitigate the risk. Here, that would be the government because it provided the Usage Reports to DynCorp.”

DynCorp said the board’s decision is a first for contract reformation due to a “mutual mistake.”

“Convincing the ASBCA to reform a government contract is an extraordinary remedy, and we believe this is the first time the Board has granted reformation based on mutual mistake,” Gregory Nixon, DynCorp’s chief legal officer, said in a statement. “The company decided to take on this five-year fight because the government clearly harmed DynCorp when it provided flawed data during the COMBS II bidding process. The ASBCA has now validated DynCorp’s long-held position.”

DynCorp lost a recompete of the T-6 services contract in late 2017 to JPATS Logistics Services.

Polsinelli PC is the law firm that represented DynCorp on its appeal.