Cybersecurity weaknesses in Lockheed Martin Corp.’s F-35 are among “many unresolved deficiencies” hobbling the costliest U.S. weapons program as production of the fighter jet ramps up, the Pentagon’s top tester said.

“The limited and incomplete F-35 cybersecurity testing accomplished to date has nonetheless revealed deficiencies that cannot be ignored,” Michael Gilmore, the director of combat testing, said in a prepared statement for a House Armed Services panel hearing Wednesday.

Gilmore’s analysis that the F-35 program “is at a critical time” expands on previous reports on the risks inherent in building the planes even as they’re still being developed. A more optimistic assessment of the fighter’s progress will be offered to the House panel by Air Force Lieutenant General Christopher Bogdan, who heads the Defense Department’s F-35 program office. Bogdan, like Defense Secretary Ash Carter, has said that the F-35 is on the right path after surmounting earlier obstacles.

The F-35 program “is executing well across the entire spectrum of acquisition, to include development and design, flight test, production, fielding and base stand-up, sustainment of fielded aircraft, and building a global sustainment enterprise,” Bogdan said in prepared testimony.

Mission Software

“Our most significant technical concern is the development and integration of mission systems software,” as each aircraft has about 8 million lines of code, Bogdan said.

The aircraft is proving its capabilities, Bogdan said, reaching 50,000 hours of flight last month. He said that included about 26,000 hours for the Air Force’s model, 18,000 for the Marine Corps version and almost 6,000 for the Navy’s, he said.

While the Marine Corps declared last July that its version of the F-35 had an initial operational capability and the Air Force plans to do so by December, Gilmore said in his statement that the F-35 “remains immature and provides limited combat capability.”

Gilmore said “the program is working to resolve the many issues it confronts, but my assessment is that the F-35 program will not be ready for” combat testing until mid-2018 at the earliest, about a year later than planned. He said in his annual report on major weapons in January that more than 500 planes would be built before the tests are completed in 2019.

The Defense Department plans a fleet of 2,443 F-35s for the U.S., plus hundreds more to be purchased by allies, including the U.K., Italy, Australia and Japan.

New Cost Estimate

The F-35 is now projected to cost the Defense Department $379 billion, or $12.1 billion less than the $391.1 billion forecast last year, according to prepared testimony by Michael Sullivan of the U.S. Government Accountability Office. The Pentagon will officially release the estimate on Thursday as part of its annual release of Selected Acquisition Reports.

Although the projected acquisition cost for the F-35 has declined since 2014, “the program continues to face significant affordability challenges” as the Defense Department deals with competing demands for programs such as a new bomber and refueling tanker, Sullivan said.

The Air Force, which is buying the biggest share of F-35s, has insisted that the program office and Lockheed fix five of the most severe software deficiencies inherited from the Marine version before it declares an initial operational capability.

The latest software delivered last month “was so unstable that productive flight testing could not be accomplished” so “the extent to which the significant outstanding deficiencies are being addressed thus far is still to be determined,” Gilmore said.

Once combat testing of the F-35 begins, Gilmore said, it will be compared against the F-16 for destroying enemy radar and the F/A-18 for other surface attacks. It’s comparison with the aging A-10 Warthog for close-air support was previously disclosed.

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