Power systems group Rolls-Royce has received an order from Japan Airlines to deliver its Trent XWB engines for a new fleet of 31 Airbus A350s.The Trent XWB, which according to Rolls-Royce is the "world's most efficient engine flying today", will power 18 A350-900 and 13 A350-100 aircraft. This follows a test flight back in June this year at the Airbus base in Toulouse, France."The Trent XWB engine benefits from a close partnership with Japanese partners Kawasaki Heavy Industries (KHI), Mitsubishi Heavy Industries (MHI), IHI Corporation, and Sumitomo Precision Products (SPP) as well as other Japanese suppliers," Rolls-Royce said.Rolls-Royce, which provides its services on land, at sea and in the air, has a customer base comprising more than 300 airlines, 4,000 corporate and utility aircraft and helicopter operators, 160 armed forces, more than 4,000 marine customers, including 70 navies, and energy customers.In other news, Rolls-Royce was also awarded two contracts worth a combined $496m to support T56 engines for US government aircraft.A six-year $406m contract will see the firm provide parts and support for T56 engines for around 1,000 C-130,P-3 and C-2 aircraft in service with the US Air Force, Navy, Coast Guard and Customs and Border Control and international fleets.Rolls-Royce has also won a $90m contract for engine repairs for the US Navy´s E-2 Hawkeye surveillance aircraft which are powered by two T56-A-427 engines.The stock was 0.17% higher at 1,116.9p in early trading on Monday.BC