Libya's Afriqiyah Airways has become the latest airline to defect from the Airbus A350-800, switching its order to the larger -900 and opting to take another four of the type.
Afriqiyah had previously ordered six A350s but the new deal takes its total to 10. They will be configured with 314 seat, says Airbus, which confirms the conversion.
The change will bring down the slow-selling A350-800's backlog to 112 aircraft. Several -800 customers have already converted to the larger type, and Airbus has been discussing similar migration with other carriers.
Despite the -800's failure to attract orders for a substantial time, Airbus has insisted that it will not cancel the twinjet programme.
The -800 is scheduled to enter service in 2016.
Airbus chief operating officer for customers John Leahy says Afriqiyah's decision to increase its order for the A350 is "a strong signal that this aircraft is the industry's new benchmark in the long-haul segment".
Afriqiyah's order takes the overall A350 backlog to 562 aircraft, including 362 -900s and 88 -1000s.