Lockheed Martin is inching closer to solving some of the technical challenges encountered with the F-35 during developmental testing.

Trials of a redesigned tailhook for the U.S. Navy F-35C, designed for aircraft carrier use, are slated for next summer; arrested-landing tests were scheduled to begin this year.

But the original tailhook design failed to snag the arresting wire in early tests due to two problems: the point of the hook was not sharp enough to scoop under the wire and securely grab it, and a damper device was not sufficient to maintain a hold on the wire. Essentially, the hook was bouncing upon landing, which reduced the likelihood of a successful arresting.

Lockheed Martin last month tested a partially redesigned version of the tailhook that features a sharper hook point but lacks the dampener that will eventually be incorporated. In three of eight recent attempts, the redesigned hook did capture the wire; the three failures occurred because the pilot landed the aircraft too far from the wire for a successful arresting. This testing “was highly successful in demonstrating that when presented the wire, . . . it will grab the wire,” says J.D. McFarlan, Lockheed Martin's vice president of test and evaluation for the F-35 program.

The failures to grab the wire were predicted by models based on where the pilots landed the aircraft, McFarlan says. This helps to validate the modeling work done on the redesigned hook, he notes. Shipboard trials are set for 2014.

Meanwhile, program officials have set aside a single aircraft for up to 90 days of tests solely of the Vision Systems International helmet that has plagued the program for more than a year with jitter, latency and other operational problems discovered in testing, says Maj. Gen. Christopher Bogdan, deputy F-35 program director.

Helmet performance is key to ramping up pilot training on the F-35, which is slated to begin early next year. Without this helmet—or possibly a backup model being quickly developed by BAE—the U.S. Marine Corps cannot declare operational capability as planned, as early as 2015. Bogdan doubts fixes to all of the problems will be implemented by then, but the government's plan to dedicate a test aircraft to the problem signals how critical the helmet is to the program's future.

Although he sees some “glimmers of hope” that production processes are improving, Bogdan notes that F-35 aircraft software is up to four months behind schedule. “There is an awful lot of software on this program. It scares the heck out of me,” he says.

Meanwhile, the latest delivery of the Autonomic Logistics and Information System (ALIS), an overall F-35 management tool, is due for November, according to Bogdan. Addressing security vulnerabilities caused the milestone to slip. Bogdan says the improved version should be validated by the middle of November, just as the Marine Corps plans to stand up its first F-35B squadron at Yuma, Ariz. Without the software improvement, the Marine jets will be grounded there, which Bogdan calls a “tragedy.”

Problems with the ALIS 1.3-version software have also held up delivery of the latest aircraft from the F-35 final assembly line at Lockheed Martin's Fort Worth plant.

The massive F-35 flight-test program is ahead of schedule in terms of planned flights and test points, Bogdan says. “From my perspective, with the test programs, we are making progress, [but] I'm not sure we are creating the right progress,” he notes.