The U.S. Department of Defence has reached an agreement with Boeing for the F-15EX program worth about $23 billion.

Boeing announced that the first two jets have begun work under the deal. Delivery of F-15EX, which is expected to replace the F-15C/Ds operational in the United States Air Force (USAF) inventory, will begin next year.

This year's fiscal budget includes delivery of eight platforms. A total of 76 F-15EX are scheduled to be in inventory during the five-year defence program, with 12 aircraft planned to be purchased in the 2021 financial year.

One of the big differences between the F-15 and F-15EX is said to be Open Mission Systems (OMS). OMS architecture enables the use of cost-effective techniques and simplified task systems integration. The F-15EX will be equipped with a new electronic warfare system and advanced cockpit, as well as advanced weapons.