Inside the Ring: F

The U.S. military's frontline F-35 fighter jet continues to face problems with key software and related issues that are delaying operational deployment, according to the Pentagon's senior weapons tester.

The U.S. military’s frontline F-35 fighter jet continues to face problems with key software and related issues that are delaying operational deployment, according to the Pentagon’s senior weapons tester.

J. Michael Glimore, director of operational test and evaluation within the Office of the Secretary of Defense, told a House hearing last week that the F-35 — which is being built in three different versions for the Air Force, Navy and Marine Corps — is “at a critical time.”

“There are shortfalls in electronic warfare, electronic attack, shortfalls in the performance of distributed aperture system and other issues that are classified,” Mr. Gilmore said March 23. “With regard to mission assistance, stealth aircraft are not visible to achieve success against the modern stressing mobile threats. We’re relying on our $400 million investment in F-35 to provide mission systems [that] must work in some reasonable sense of that word.”

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The F-35 program will spend $1.13 trillion to buy and service more than 2,400 aircraft until 2070. Each F-35 costs about $100 million. The jet is needed to replace older, less-capable warplanes.

The program has been plagued with development problems under the Obama administration since Defense Secretary Robert M. Gates killed the F-22 fighter bomber in 2009. The scrapping of the F-22 left the F-35 as the sole radar-evading stealth aircraft for the future.

Mr. Gilmore testified that the F-35 system remains “immature” and “provides limited combat capability,” despite the Marines declaring their F-35s as having initial operating capability and the Air Force planning to do so later this year.

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Flight tests of new software for the jet, known as Block 3i, revealed “many unresolved significant deficiencies,” he added.

The software “was so unstable that productive flight testing could not be accomplished,” Mr. Gilmore said, adding that the software is less stable than earlier software it replaced.

The software stability problem involves frequent timing errors between radar sensors and onboard computers during takeoff. The problem results in system restarts and subsequent difficulties for computers in regaining radar pictures several minutes after restarting.

The jet manufacturer Lockheed Martin is working to remedy the problem within the software’s 8 million lines of code.

Earlier software problems prevented testing weapons’ delivery accuracy until better software for the avionics was installed.

“A recent example is an attempted four-ship electronic warfare ‘Super Scenario’ mission with Block 3F software that resulted in only two aircraft arriving at the range because the other two aircraft ground-aborted due to avionics stability problems during startup,” Mr. Gilmore said.

Additionally, when the F-35 was flown against a dense and realistic electronic warfare airspace, the avionics were unable to detect targets and had difficulty applying sensor information.

As of the end of January, the testers found 931 software program deficiencies, including 158 considered so severe that the glitches could “cause death, severe injury, or . [that] may cause loss of or major damage to a weapon system; [or] critically restricts combat readiness capabilities,” Mr. Gilmore said.

The aircraft is also vulnerable to cyberattacks.

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