Singapore Airlines has signed a contract for 20 Airbus A350-900 XWB aircraft for US$3.7 billion at list prices, with options to buy 20 more, affirming the letter of intent signed last July.

The A350 XWB is an Airbus next generation twin-engine aircraft for medium to long-haul flights. Deliveries for the first 20 aircraft are scheduled to begin in 2013 and run through to 2015.

The purchase of the aircraft, including engines and spares, is intended to improve the carrier's operational efficiency and environmental performance. The order will cater for future growth, as well as maintain Singapore Airlines' policy of operating a young and modern fleet, a statement from the carrier said.

The A350-900 XWB has a range of 8,100 nautical miles, enabling the airline to fly to Europe, Australia, the Middle East and Asia. The aircraft can carry over 20 tonnes of cargo, has a wingspan of 64 metres and measures 64 metres in length.