The Lockheed Martin F-35 program is facing manufacturing inefficiencies, parts problems and at least six engineering technical challenges, according to the U.S. Government Accountability Office (GAO). In its latest report to Congress on the F-35, the GAO said that despite the recent adjustments to the development and initial production program ordered by the Office of the Secretary of Defense (OSD), “restructuring is not finished and further cost growth and schedule extensions are likely.” The GAO has been sniping at the F-35 program for years, but its criticisms have been given added credibility by the OSD’s own studies that contradicted the optimism coming from the F-35 Joint Program Office and Lockheed Martin. Because of the increases in cost predicted by the OSD’s studies, the F-35 program will formally breach the Nunn-McCurdy statute, which requires the Pentagon to report programs that go over budget, for a second time. As a result, the Pentagon must now produce new documentation for Congress and formally certify that the F-35 program is still needed. Responding to the GAO report, a Lockheed Martin spokesman described major recent advances in production efficiency to AIN. The time required to manufacture an F-35 has dropped by one third, and labor hours have been halved, he said. “Traveled work” after rollout is now less than 150 hours per aircraft (compared with more than 1,000 hours previously), with only 16 parts missing on the latest rollout, compared with 300-plus previously, he added.