Singapore Airlines will start flying nonstop between San Francisco and Singapore beginning in October, a route that will test the range of the carrier’s new Airbus A350s.

Singapore had not planned to resume nonstop flights to the United States until 2018, after it took delivery of a special long-range version of the A350, Airbus’ newest widebody. But competitor United Airlines apparently forced its hand, with the Chicago-based airline starting its own San Francisco-Singapore nonstop on June 1. At 8,446 miles, the route is among the world’s longest, and few aircraft have the range to fly it.

The new route will begin on Oct. 23, 2016 using a 253-seat Airbus A350-900.

What is interesting is that neither Singapore’s A350 nor United’s Boeing 787-9 is the perfect aircraft for the mission. Each lacks the range to fly nonstop with a full load of passengers and cargo in winter, when headwinds are strongest. But aircraft can fly farther when they are not full, and both Singapore and United have suggested they will not sell every seat in the winter, when range is a concern. This should allow the carriers to fly the route year-round.

Singapore likely would prefer to fly from Los Angeles or New York, where demand for nonstops is strongest, and the airline has said it will fly to both cities in two years once it receives the long-range version of the A350. But San Francisco is slightly closer to Southeast Asia than New York or L.A, making the city a more logical gateway for a range-challenged aircraft. Seattle likely would have been the only other large U.S. city that could support a nonstop flight.

Singapore and United are both Star Alliance members, but they are fierce competitors, and each believes the U.S.-Singapore route is vital to its interests. Industry insiders often say Singapore has some of the most favorable business and first class fares in the world because of a status as a business hub.

Singapore previously flew nonstop from Newark and Los Angeles, but it stopped both routes in 2013. Singapore was using gas-guzzling Airbus A340s outfitted with only 100 seats, all in business class, and when fuel prices spiked, the routes became difficult for the carrier to operate.

The twin-engine A350 is far more efficient, and even with some seats blocked at times, the operating economics should be more favorable .

Photo Credit: Singapore Airlines had planned to wait for a long-range version of the Airbus A350 before restarting nonstops to the United States, but the carrier changed its mind. Airbus