The scale of the proposed expansion extends production far beyond the programme’s current baseline. That longer manufacturing run means some components used in the initial configuration will no longer be available for later aircraft.
The Air Force established the extended procurement concept in February 2026, leaving limited time to define its full technical and financial impact. The report says the plan introduces new cost and schedule uncertainties at the same time that the programme is preparing for a substantial increase in aircraft numbers.
Lots 1 through 8 rely on proven subsystems to reduce the risk of delays during production and fielding. The Lot 9–12 configuration introduces several new subsystems, including a new radar and mission-computing architecture, with fielding scheduled to begin in January 2031.
The planned electronic warfare upgrade is identified as EPAWSSv2, a new version of the Eagle Passive Active Warning Survivability System. The report does not disclose the manufacturers or specific models under consideration for the replacement radar, mission computer or engines.
The Air Force describes the combined changes as a “significant redesign effort” driven by diminishing manufacturing sources and material shortages. That work adds an extensive development and integration programme to what was initially structured around mature technology.
The redesign has not yet been fully costed. The programme lacks both an approved Program Office Estimate and an independent Non-Advocate Cost Assessment for the expanded procurement.
Government estimates are being used to establish the initial budget requirement while contractors conduct studies on the likely cost and schedule. The programme office has launched an accelerated estimating process to inform the fiscal 2028 President’s Budget request.
The Air Force plans to divide testing and integration of the modernised subsystems among future Operational Flight Program releases scheduled from fiscal 2031 through fiscal 2035. This approach is intended to reduce integration risk and introduce the new equipment without interrupting the F-15EX production line.
Research, development, testing and evaluation costs are now estimated at $1.57 billion in constant fiscal 2020 dollars, or $1.93 billion in then-year dollars. The report attributes the increase beyond the approved threshold to the 170 additional aircraft and the development and testing needed to address component obsolescence.
The final cost of the later production batches also remains open. Lots 1 through 6 are fully funded at fixed-price incentive levels, but prices for Lots 7 through 12 will be negotiated under future contracts.
The Air Force expects multiyear procurement negotiations to help control prices for those aircraft. The absence of approved cost estimates for the redesign, however, leaves a central part of the expanded programme dependent on preliminary government assumptions and contractor studies.
Software for the aircraft is developed and fielded through the separate F-15 Continuous Development and Integration programme, which also supports the F-15C, F-15D and F-15E. The report identifies no significant software-related problems with the F-15EX programme at present.
The two-seat F-15EX Eagle II is derived from the F-15QA configuration developed for Qatar and incorporates Air Force-specific electronic warfare and mission software. It is intended primarily to replace ageing F-15C and F-15D aircraft in defensive and offensive counter-air missions.
