passengers in a single-class layout. The A350 Regional was expected to be ordered by Etihad Airways and Singapore Airlines. Since 2013, there has been no further announcement about this variant. Singapore Airlines selected an A350-900 version for medium-haul use, and Japan Airlines took delivery of a 369-seat A350-900 with a MTOW for its domestic flight network. The A350 Type Certificate Data Sheet includes MTOWs of 217, 235, 240, 250, 255, 260, 268, 272, 275, 277, 278, 280 and 283 t. A350-1000 The A350-1000 is the largest variant of the A350 family at just under in length. It seats 350-410 passengers in a typical three-class layout with a range of . With a 9-abreast configuration, it is designed to replace the A340-600 and compete with the Boeing 777-300ER and 777-9. Airbus estimates a 366-seat -1000 should have a lighter operating empty weight than a 398-seat 777-9, a 15% lower trip cost, a 7% lower seat cost, and a 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 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. The A350-1000 has an 11-frame stretch over the −900 and a slightly larger wing than the −800/900 models with trailing-edge extension increasing its area by 4%. This will extend the high-lift devices and the ailerons, making the chord bigger by around , optimising flap lift performance as well as cruise performance. The main landing gear is a 6-wheel bogie instead of a 4-wheel bogie, put in a one frame longer bay. The Rolls-Royce Trent XWB engine's thrust is augmented to . These and other engineering upgrades are necessary so that the −1000 model maintains range. It features an automatic emergency descent function to around and notifies air traffic control if the crew fails to respond to an alert, indicating possible incapacitation from depressurisation. The avionics software adaptation is activated by a push and pull button to avoid mistakes and could be retrofitted in the smaller -900. All performance targets have been met or exceeded, and it remains within its weight specification, unlike early −900s. Its basic MTOW was increased to before offering a possible version. Its 316 t MTOW appeared on 29 May 2018 update of its type certificate