Airbus A350-900ULR

The A350-900ULR (Ultra Long Range) is the version of the A350-900 built for a single purpose: to link, non-stop, cities separated by more than half the globe. It did not grow out of a generic market requirement but out of one specific customer, Singapore Airlines, which wanted an aircraft able to fly from Singapore to the US east coast with paying passengers and without operational restrictions. Airbus answered without designing a new aircraft: it took the margin already present in the -900 airframe and pushed it to the limit.

In Airbus's internal nomenclature the version is weight variant 13 (WV013). Its maximum take-off weight rises to 280 t, five tonnes more than the certified 275 t variant it derives from, with a maximum landing weight of 207 t and a maximum zero-fuel weight of 192 t. The decisive change is fuel: capacity grows from 141,000 to 165,000 litres with no auxiliary tanks fitted. Airbus modified the fuel system to use spare volume in the centre wing box, so the extra fuel is carried within the existing structure. Because there are no further structural changes, the aircraft keeps the type certificate and model designation of the baseline A350-941; from the outside it is identical to a standard -900.

The logic is operational arithmetic. At an average burn of about 5.8 t of fuel per hour, flying 19 hours instead of the usual 15 requires roughly 24 t more fuel. The higher take-off weight and a lower payload make that reserve possible. In exchange, the forward cargo hold is disabled because of operating limits, although it can be reactivated if the customer needs it. The result is a range of 9,700 nautical miles (18,000 km), which Airbus describes as the longest of any commercial airliner in service and which still held that title in 2023; non-stop flights can exceed 20 hours.

The -900ULR was also the first aircraft to carry the aerodynamic improvements of the performance package Airbus had been testing since October 2017: extended winglets and a modified wing twist to optimise the spanwise load distribution, features later extended to the other versions. The first example was rolled out in February 2018, still without engines, for ground testing. Once the engines were installed, flight tests checked the larger fuel capacity and measured the gains from the new winglets. It flew for the first time on 23 April 2018.

Singapore Airlines, the launch customer, placed a firm order for seven, counted within its overall A350-900 order. It took delivery of the first in September 2018; its chief executive, Goh Choon Phong, spoke of having pushed the limits to extend long-range flying to new lengths. The cabin was laid out in just two classes: 67 business seats and 94 premium economy seats, with no economy class. The airline had planned layouts ranging from 170 seats, mostly business, to more than 250 in mixed configuration, and the aircraft can be reconfigured. Airbus and the airline highlighted higher ceilings, larger windows, a quieter cabin, lighting designed to reduce jet lag, and better cabin altitude and humidity thanks to the composite fuselage.

Entry into service came on 11 October 2018. That day the first non-stop flight from Singapore Changi to Newark Liberty, in the New York area, took off as the world's longest commercial flight at the time. It landed on 12 October after 17 hours and 52 minutes in the air, having covered 16,561 km for a great-circle distance of 15,353 km and burned 101.4 t of fuel. The first two aircraft were assigned to the New York route and the following ones to Los Angeles, opened on 2 November 2018, and to extra frequencies to San Francisco. With them, Singapore Airlines would link Singapore and the United States with 27 weekly non-stop flights by the end of 2018.

Over time the New York service moved to JFK: in 2022 the -900ULR was flying Singapore Airlines Flights 23 and 24 between Singapore and New York, then the longest scheduled flight in the world. The version also left its mark on the ordinary A350-900: from 2020 Airbus offered the -900 with the ULR's 280 t maximum take-off weight. Its conceptual successor is the A350-1000ULR ordered by Qantas which, unlike the -900ULR, does add a rear centre tank built into the structure.