AirAsiaandAirAsia Xhave sought to distance themselves from allegations that their directors sought to gain advantage from an engine maintenance deal with Rolls-Royce.

The engine manufacturer recently agreed to a �671 million settlement with the UK Serious Fraud Office (SFO) to avoid prosecution over allegations of corruption involving engine and power deals in the Asia-Pacific region.

In a Statement of Facts released by the SFO alleged that an unnamed "AirAsiagroup executive" had sought credit for engine services on a privately-owned Bombardier Global Express business jet.Over two years, Rolls-Royce struggled with the issue, and ultimately applied a USD 3.2 million credit to the service account for the jet.

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In a statement to the Malaysian stock exchange,AirAsia Xsays it has “long established good and open business dealings with Rolls-Royce”.

“AirAsia X, its directors and officers have never sought personal favours or gratification from Rolls-Royce other than to negotiate for the best possible commercial and financial terms for the benefit of the company,” it adds.

Flight Fleets Analyzer shows that the long-haul, low-cost carrier operates 22 Airbus A330-300s that are powered by R-R Trent 700 engines, which are covered under a TotalCare service agreement with the manufacturer.

In a separate stock exchange statement,AirAsiadeclared that it “had no dealings or transactions with Rolls-Royce”, and clarified its relationship with the Global Express noted in the SFO’s statement.

It says that the jet in question is owned by Caterhamjet Global, which is a related party to the airline. Under its agreement with the jet’s owner,AirAsiamade an annual contribution of USD 3 million for its upkeep, which was used by its executives.

In June 2016,AirAsiaentered into an agreement to buy the aircraft, but says that completion of that deal is still pending.

Both carriers add that they secured all required approvals for their dealings with the Global Express from shareholders and their audit committees.

The investigation into Rolls-Royce also implicatedThai Airways InternationalandGaruda Indonesia, which have started their own internal investigations into their dealings with the manufacturer.