Airbus's A350-1000 has completed fuel system tests in the UK as part of the twinjet's certification programme.
One of the three test aircraft, MSN71, was flown to Cardiff where the tests were performed over 3-4 May.
Airbus engineers from its Filton facility assisted the testing, which assessed fuel-management system behaviour in simulated hot-climate conditions.
"The aircraft was fuelled twice a day and then the flight-test team performed a number of required engine and systems flight tests with hot fuel," says the airframer.
Early results have shown that the system "efficiently" handles a variety of fuel densities at different temperatures, it adds, including fuel flow to the Rolls-Royce Trent XWB-97 engines and between the fuel tanks.
Airbus says the A350-1000 is "ready for hot-conditions operations" from entry into service. Qatar Airways will be among the early recipients of the aircraft.