The Marine Corps will redesign the aluminum bulkheads on the F-35B to prevent cracking, which was discovered on one plane in February after nearly 10,000 hours of testing, Commandant of the Marine Corps Gen. James Amos said Tuesday.
The structural bulkhead of the plane is made of aluminum to minimize weight, but engineers discovered cracks in it during dynamic testing after about 9,800 hours–past the expected 9,000-hour service life of the plane, Amos said at the American Enterprise Institute. Despite the cracks occurring so late in the life of the plane, Amos said “it doesn’t mean it doesn’t need to be fixed.”
Engineers announced they found a solution about a week ago, Amos said, though the service is in no hurry to retrofit planes or work the fix into the production lines.
“We’ve got years before we have to go back and retrofit” planes already delivered by manufacturer Lockheed Martin [LMT], since most planes are at 1,000 flying hours or fewer, he said. That flexibility means the Marine Corps/Lockheed Martin team can wait for the most opportune time for the work, which will involve taking the wings off the plane. While the planes are disassembled, Marines may as well make other fixes or upgrades as needed.
For now, Amos said the engineers will manufacture, install and test their fix to make sure it works as planned. He added that new planes, beginning around Low-Rate Initial Production Lot 7, would be built with the sturdier bulkheads.
Aside from the bulkhead cracking, Amos said the F-35 program “is probably about as healthy as it has been in the past.” Software will always be a challenge, he said, noting it had 6 million lines of code compared to only 2 million in the F-22 software. But he said the software engineers had “progressed quite well.” He added that the Marines seemed to have worked out all their problems with the F-35 helmet and that training operations in the first F-35 squadron in Yuma, Ariz., were going well too.