The plane, an enhanced version of an aircraft first flown in 1975 and designed to replace the aging F-15C/D variants, arrived at Eglin Air Force Base, Fla., for testing. It joined the first F-15EX, which was delivered to the base in March.
Upgrades to the plane known as the Eagle II include advanced avionics systems and the capability of carrying nearly 30,000 pounds of air-to-air and air-to-ground weapons internally, to minimize its stealth profile.
The variant is based on the F-15QA model, built for Qatar's air force.
In 2019, the Department of Defense outlined plans to spend nearly $7.9 billion over the next five years to replace its F-15 fleet with the improved versions of the fighter aircraft.
The Fiscal Year 2021 budget request includes 12 more aircraft, with up to 76 over the next five years. The Air Force intends to acquire at least 144 Eagle II planes overall.
The first six aircraft to be delivered will be used for developmental and operational testing. They can be modified later for use as operational airframes, officials have said.
Boeing received the contract in July 2020, a $1.2 billion award for the first eight F-15EXs, which included a ceiling of $22.89 billion for up to 200 planes.
A Boeing statement on Wednesday noted that the second F-15EX was delivered to the Air Force ahead of schedule.
It added that the plane is "a ready-now replacement for the F-15C that includes best-in-class payload, range and speed and an all-new digital infrastructure."
"With its large weapons capacity, digital backbone, and open architecture, the F-15EX will be a key element of our tactical fighter fleet and complement 5th-generation assets," Lt. Col. Sean Dorey of the Air Force Life Cycle Management Center said in March.
"In addition, it's capable of carrying hypersonic weapons, giving it a niche role in future near-peer conflicts," Dorey said.
