The House Appropriations Committee defense panel is proposing the allowance of more than nine developmental test F-35 fighters.
Section 219 of the fiscal 2025 National Defense Authorization Act increased the number of developmental test aircraft in a Lot 18 or later buy from six to at least nine–three of each U.S. Air Force, Marine Corps, and Navy variant–under the F-35 Continuous Capability Development and Delivery (C2D2) effort. Such planes are to field by 2030.
The HAC-D fiscal 2026 bill spells out the “at least” 9 in more detail.
“The secretary of defense may obligate funds made available by this act for procurement or for research, development, test and evaluation for the F–35 Joint Strike Fighter to modify not fewer than nine F-35 aircraft, including at least three F–35 aircraft of each variant, for any test configuration–provided that the secretary of defense shall, with the concurrence of the secretary of the Air Force and the secretary of the Navy, notify the congressional defense committees not fewer than 30 days prior to obligating funds under this section,” according to Section 8123 of the HAC-D bill.
The latter would also prohibit the allocation of any funds “to integrate an alternative engine on any F-35 aircraft.” RTX‘s [RTX] Pratt & Whitney makes the F-35’s F135 engine.
Begun in 2018, C2D2 for the Lockheed Martin [LMT] F-35 envisions software updates for the fighter every six months and has included the development of Block 4, Technology Refresh-3 (TR-3) to permit the Block 4 advancements and making F-35s capable of carrying conventional and nuclear ordnance. Cost estimates for C2D2, which the F-35 program is to pursue through fiscal 2025, have varied from $7 billion to more than $10 billion.
As the F-35 program aims to deliver a “fully combat capable” fighter this year with TR-3, a significant part of the effort is rejuvenating laboratory capacity.
Lockheed Martin said last year that it is investing $350 million over five years for such capacity.