The Senate Appropriations Committee’s draft fiscal 2022 defense funding bill recommends cutting nearly $566 million from the Pentagon’s almost $2 billion request for Continuous Capability Development and Delivery (C2D2) for the Lockheed Martin [LMT] F-35 fighter.

Under C2D2, F-35s are expected to receive software updates every six months. Begun in 2018, C2D2 has included the development of Block 4 software to prepare the aircraft to counter area denial by adversaries, Technology Refresh-3 updates, 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.

An explanatory statement for the Senate Appropriations Committee’s bill noted “significant challenges” facing C2D2. They include “cost growth of approximately 70 percent, schedule delays of the Technology Refresh 3 system, and a three-year delay in the delivery of the complete Capability Increment #1 (formerly Block 4) capabilities,” per the statement. “In addition, the committee remains concerned that clearly quantifiable metrics for contract performance and deliverables of software-based capabilities remain inadequate and are not linked to prior year budget execution or the pending budget request.”

The committee said that it would thus not support the requested nearly $566 million increase for C2D2 in fiscal 2022 and that it is directing the Pentagon to “break out C2D2 from the existing F-35 acquisition program as a separate Major Defense Acquisition Program for oversight and reporting purposes.”

The draft Senate defense funding bill for fiscal 2022 mostly adheres to the DoD request for new F-35s, including more than $4 billion for 48 Air Force F-35As, $2.2 billion for 17 U.S. Marine Corps’ F-35Bs, an $2 billion for 20 U.S. Navy F-35Cs.

A slow software loading process for the F-35A has delayed aircraft updates under C2D2, but an Air Force official said in March that the service had resolved that for Tape 6–the latest software drop–that Combat Air Forces was to field over the last several months (Defense Daily, March 18).