China Southern Airlines, the largest airline by fleet size in Asia, announced on November 6 it signed a letter of intent with British aero engine maker Rolls-Royce Holdings PLC to purchase engine total care service.

It marked one of the largest civil aviation orders signed during the ongoing second China International Import Expo in Shanghai, according to the airliner.

According to the letter of intent, Rolls-Royce will provide after-sale, pay by hour service, spare engine support and some other services for engines on 20 A350 aircraft between 2019 and 2034.

China Southern ordered 20 A350 aircraft in 2017, with the first delivered in June this year. The carrier expects to receive, accumulatively, the remaining A350s by 2022.

The aircraft will be the main model flying at the Beijing Daxing International Airport, which went into operation in September.