China Airlines has signed a memorandum of understanding with Boeing for three firm 777 Freighter orders with the option for another three.

The 777Fs will be used on flights to Europe and North America, replacing older 747-400Fs in service. China Airlines says the 777Fs offer efficient operations and better economics than the older aircraft.

ULDs for 777Fs and 747-400Fs are compatible, which China Airlines says leads to smooth transit cargo handling. The airline says that compared to the 747-400F, the 777F offers fuel savings of more than 20%.

China Airlines added 10 777-300ER passenger aircraft to its fleet between 2014 and 2016. The Taiwanese airline says that both aircraft use the same GE90 engine, reducing maintenance costs. With common type pilot deployment, the airline also says the a 777-300ER pilot could easily fly a 777F after receiving difference training.