WASHINGTON

US F-35 fighter jets were mission-ready roughly half the time in 2024 because of maintenance issues with Lockheed Martin, a Pentagon watchdog said in a report.

The report, from the Defense Department's Office of the Inspector General issued on Dec. 19, said the Defense Department did not adequately oversee contractor performance on the June 2024 air vehicle sustainment contract.

"Although the F‑35 JPO (Joint Program Office) monitored Lockheed Martin’s performance, it did not always hold Lockheed Martin accountable for poor performance related to F‑35 sustainment.

"This occurred because the F‑35 JPO did not include aircraft readiness performance or other measurable contract requirements and did not enforce material inspection and government property reporting requirements in the air vehicle sustainment contract," it said.

The report said the Pentagon paid Lockheed Martin $1.7 billion without any economic adjustment, although the jets "did not meet the minimum requirements of the Military Services."

The F‑35 program is the Pentagon’s largest acquisition program with an estimated cost of over $2 trillion to buy, operate and sustain the F‑35 over its lifetime.

The F‑35 Joint Program Office is responsible for F‑35 production and sustainment contracting, as well as maintaining a comprehensive sustainment plan, according to the report.