International Airlines Group (IAG), the parent company of British Airways, is committing to a purchase of up to 42 Boeing 777X aircraft, with 18 of them being firm commitments. The purchase is valued at approximately $18.6 billion at list prices. Once finalized, it will appear on Boeing’s Orders and Deliveries site.

The purchase is aimed at replacing the Boeing 747, a four-engine aircraft that is being phased out of passenger service in many airlines around the world. With the 777X, British Airways will be able to obtain better cost efficiencies of up to 30% compared to the Boeing 747 currently in service.

British Airways has one of the largest fleets in the airline industry with about 275 aircraft in service and serves over 160 destinations. The airline is undergoing a fleet modernization to improve service across its network. Recently, investments include the Boeing 787 Dreamliner to replace medium-size jets.

Currently, there are nearly 60 Boeing 777 aircraft flying for British Airways. Last year, British Airways committed to four additional Boeing 777-300ER aircraft. The new 777Xs will increase the airline’s already substantial 777 fleet.

Compared to current Boeing 777s, the 777X has a cabin that is slightly wider. In a two-class arrangement, 400-425 passengers can be seated. The cabin helps improve the passenger experience with the wider cabin, new lighting, better cabin altitude, improved humidity levels, and reduced sound. To achieve increased efficiencies for the operator, the 777X borrows technology from the Boeing 787 Dreamliner. Paired with a brand new composite wing design with folding wingtips, the 777X offers nearly 12% less fuel consumption than other aircraft in its class.

With the announcement from IAG and British Airways, the Boeing 777X is currently at 358 orders and commitments. The first 777X began production in 2017 and the first flight is planned for later 2019. Airlines are expected to receive aircraft starting in 2020.