Airbus has started listing the A350-1000 as having a maximum take-off weight of 319t, around 3t higher than any of the current weight variants featured in its most recent detailed technical data documents.
The airframer had previously confirmed to FlightGlobal that it was looking at a higher MTOW figure.
Nine weight variants are contained in its technical data documentation for airport planning, including two – designated 002 and 011 – at the highest MTOW of 316t.
This gives the usable fuel capacity of the A350-1000 as 156,000 litres.
Airbus's official promotional material, however, puts the aircraft's MTOW at 319t and hikes its usable fuel capacity by 2% to 159,000 litres.
This brings the A350-1000's range up to 8,700nm from its previous 8,400nm.
Although the airport planning documentation is yet to include weight variants with the enhanced figures, Airbus has been quietly acknowledging the MTOW and fuel increase in its own publications for several months – an aircraft family presentation from April includes the higher-weight data for the variant.
The enhanced performance is also listed in a revised media 'facts and figures' briefing for October 2019.
Airbus has highlighted the increased range as it pushes the A350-1000 as a contender for Qantas's ultra-long range Project Sunrise programme.
It has already developed a specific ultra-long range version of the smaller A350-900, but this aircraft – the A350-900ULR – has particular design changes, including a modified fuel system involving relocation of sensors and piping.
The -900ULR also has a higher fuel capacity – totalling 165,000 litres – than the 138,000 litres of the basic -900, but its typical accommodation is reduced to 173 seats in order to achieve its 9,700nm range.
Airbus has not specified how it will adapt the A350-1000 to meet the demands of Project Sunrise, but has indicated that no further MTOW increase is planned, and that the 319t version – which will become the baseline variant in the early 2020s – is the version being put forward for Qantas.
Head of A350 marketing Marisa Lucas-Ugena shies away from describing the offer as a -1000ULR version, which suggests the airframer is not looking at the same level of modification as it undertook for the -900ULR.
Project Sunrise aims to provide nonstop service to Australian cities such as Sydney, Melbourne and Brisbane from London and New York.
Airbus has indicated that it could end up providing both the -1000 and the -900 to Qantas for the programme. But while the Australian sectors from New York and London differ in range requirement, Airbus says it is not looking at splitting the models between these routes but rather committing to offering the -1000 for Sunrise services from both cities.