The A350-1000 is the largest variant of the A350 family at just under 74 metres (243 ft) in length. It seats 350-410 passengers in a typical three-class layout with a range of 8,700 nmi (16,100 km; 10,000 mi). With a 9-abreast configuration, it is designed to replace the A340-600 and compete with the Boeing 777-300ER and 777-8. Airbus estimates a 366-seat -1000 should have a 35 tonnes (77,000 lb) lighter operating empty weight than a 398-seat 777-9, a 15% lower trip cost, a 7% lower seat cost, and a 400 nmi (740 km; 460 mi) greater range. Compared to a Boeing 777-300ER with 360 seats, Airbus claims a 25% fuel burn per seat advantage for an A350-1000 with 369 seats. The 7 m (23 ft) extension seats 40 more passengers with 40% more premium area. The -1000 can match the 40 more seats of the 777-9 by going 10-abreast but with diminished comfort.
(Source: Wikipedia)