The new-build F-15 was not part of the service’s original budget plans, but was added because the type has lower lifetime operating costs, the USAF acknowledges. The service is committed to buying 72 fighters per year, but cannot afford to purchase only F-35As because of that aircraft’s high operating costs – which average about $35,000 per hour.
“Our challenge was when you look at the force structure that we have there were four fourth-[generation] airplanes – F-16, F-15E, A-10 and F-15C – that we need to fly in [the] 2030s. The F-15C is not going to make it. It is old and it is not going to fly past the mid-20s,” USAF chief of staff General David Goldfein said in testimony to the US Senate Appropriations Committee on 13 March.
“We used the best cost estimate that we had at the time and looked at the various options. The most affordable options – as long as we keep the F-35 absolutely on track with our programme of record – was to look at an F-15 variant to replace the F-15C.”
As part of the Department of Defense’s fiscal year 2020 funding request, the USAF is initially requesting $1.1 billion for eight F-15EXs. The service plans to request 80 of the aircraft in total over the next five years, costing roughly $80 million each. The first F-15EXs are expected to be delivered in FY2022.