Lockheed Martin Corp.’s F-35 fighter jet has passed its initial radar-evasion testing and there are no “major potential changes contemplated for any of the stealth design,” according to the U.S. program office.
The program office has collected radar cross-section information on the Air Force version of the aircraft and “we are very pleased, very pleased,” U.S. Navy Vice Admiral David Venlet, the program manager, said in an interview.
Still, “this is not a one-test ‘Eureka’ and it’s done,” he said. The Air Force version will comprise the greatest number of the 2,457 planned F-35s.
Venlet said he expected similar results from the Navy and Marine Corps short-takeoff-and-vertical-landing versions when they are tested. Lockheed Martin in November measured two early-production Air Force models, which also passed with no “major variances,” Venlet’s office said.
“So we do not have major concerns,” Venlet said. “We are always going to pay attention to it, because if you don’t, it will always be a source of rework and cost growth. But as early as we are, we are very pleased.”
The F-35 is being developed as the Pentagon’s premier fifth-generation stealth fighter, capable of penetrating the heaviest enemy air defense. When fielded, it would join the B-2 bomber and the F-22 fighter in the U.S. stealth jet inventory.
The Pentagon’s Defense Contract Management Agency told congressional investigators that it had “noted difficulties” with Lockheed Martin manufacturing of the aircraft’s outer surface, or “mold line.” The process involves detailed attention to the skin’s finish, fasteners and drain holes that affect an aircraft’s radar-evading profile.
The U.S. Government Accountability Office, in an F-35 report last month based on DCMA input, said the “inability to meet the outer mold line requirements could have major impacts on cost as well as stealth requirements and capabilities.”
“This problem is not expected to be resolved until the June 2015 time frame, after which a large number of aircraft will have been built and would need to be retrofitted for any design changes,” the GAO wrote.
Venlet said the DCMA raised valid concerns and reflected “signs of the early attention being paid” to outer mold line manufacturing tolerances “because it can’t get out of control.”
The DCMA’s reports “are extremely accurate, and we act on them,” he said. “It triggered attention, drove action.” Action has been taken to “optimize production for stealth requirements,” his office said.
Lockheed Martin spokesman Michael Rein said in an e-mail that “while there are challenges in holding tight tolerance specifications, all F-35s are meeting the requirements and are compliant in form, fit, function and stealth.”
“Manufacturing improvement processes and changes are in place to address tolerance challenges,” Rein said, and more changes are being made “to continually improve the product.”