Thomas McArtor, a former quality control officer who worked from 2003-06 at the company's plant in Indianapolis, filed suit in 2008 claiming he was wrongfully dismissed for "refusing to cooperate," with the company's allegedly substandard quality control practices.
The lawsuit says he would not cooperate in "knowing deviations from its quality control plan."
The Daily Telegraph reported Saturday McArtor was joined in his lawsuit by a second quality control officer, Keith Ramsey, in 2011. The two are contesting in court their right to go public with some of their accusations, which have been kept away from the public by a court order.
The suit alleges the company used parts designated for scrap in products sold to customers, including the U.S. military.
The BBC said Rolls-Royce has denied the allegations, noting that Judge William Lawrence had thrown out two of four allegations in the discovery phase of the lawsuit.
"Judge Lawrence did not find that Rolls-Royce engaged in any wrongdoing, failed to follow its quality system, concealed anything from the US government or even that a jury is entitled to hear the allegations," the company said in a statement.
"Rolls-Royce categorically rejects the other claims and will defend itself vigorously.
"Any and all facts of the case will be presented in court, where we are confident it will be found the lawsuit is without merit," it added.