Qantas chose Airbus’ A350-1000 over Boeing’s delayed 777X as the preferred plane for its ultra-long-haul, non-stop research flight program, Project Sunrise, after evaluating both planes.

Qantas is trying to fly regular, non-stop commercial flights from the east coast of Australia to London (LHR) and New York (JFK). It said it will make a final decision on whether to operate the flights by March 2020.

The research flights are being conducted to try out ways to improve the health and comfort of passengers and crew on such long flights.

To better accommodate the route, Airbus will add an additional fuel tank and slightly increase the maximum takeoff weight to “deliver the performance required for Sunrise routes.” Qantas has not placed orders yet.

Meanwhile, Boeing is seeing delays with its 777X program. The company suspended load testing of the new plane in September when it failed a ground stress test. Qantas said the choice of Airbus over Boeing for Project Sunrise was not tied to 777X program issues.