China’s Hainan Airlines is finalizing terms with Boeing on a purchase agreement for 50 737 MAX 8s, valued at $5.1 billion at list prices.

The pending order, subject to approval by the Chinese government, was announced Wednesday at the Farnborough Airshow. “A long time, we’ve tried to get this deal done,” Hainan Group vice chairman and president Adam Tan told reporters. “I’m so happy today we can get it done.”

Among a diverse fleet, Haikou-based Hainan currently operates nearly 100 737-800s. “The 737 is the backbone of our single-aisle fleet,” Tan said. No delivery dates for the 737 MAX 8s were provided.