Singapore Airlines has ordered 39 new aircraft from Boeing Commercial Airplanes, including 20 777-9Xs and 19 787-10 Dreamliners. While that order is reportedly worth $13.8 billion, Boeing also noted that Singapore Airlines recommitted an earlier order for 30 787-10 aircraft.

The 777X will be a redesigned version of the 777, the long-range, wide-body jet that is the world’s largest twin-engine aircraft. It is intended to compete with the new Airbus A350, and will be available in three models, the 777-8X, 777-9X.

While the first 777X jets are not scheduled to debut until 2020, Boeing reportedly has over 300 orders and commitments for the jets from Lufthansa, Etihad Airways, Cathay Pacific, Emirates, Qatar Airways, All Nippon Airways, and other unidentified carriers. Singapore Airlines is slated to be the launch customer for the 777-10X.

"Singapore Airlines has been a valued Boeing customer for more than 50 years and we are honored they have selected the 777X and additional 787-10s to expand its future widebody fleet. They are the most efficient, capable and passenger-preferred airplanes in their class," according to Kevin McAllister, president and CEO for Boeing Commercial Airplanes.

Singapore Airlines’ announcement also represented good news for GE Aviation, which is developing the GE9X engine to power the 777X series. The carrier’s order will mean a subsidiary contract to GE Aviation for 45 GE9X engines, which the engine builder estimated to be worth more than $2.0 billion.

The first GE9X completed testing in 2016, flying-testbed testing is expected this year, with engine certification scheduled for 2018.

According to Ted Ingling, GE9X general manager at GE Aviation, "The new GE9X engine has performed flawlessly through initial testing. With more than 700 engines on order, it has become one of the fastest selling wide-body engines for GE Aviation."