Marine F-35 gets another delay because of cracks in bulkheads

Bloomberg/Stars & Stripes:

On-the-ground stress testing for the Marine Corps version of Lockheed Martin Corp.'s F-35 jet may be halted for as long as a year after cracks were found in the aircraft's bulkheads, Pentagon officials said.

Testing of the fighter's durability was stopped in late September after inspections turned up cracks in three of six bulkheads on a plane used for ground testing, said Joe DellaVedova, spokesman for the F-35 program office.

The previously undisclosed suspension of the stress testing may increase scrutiny of the Marine Corps' F-35B, the most complex of the three versions of the plane, during congressional hearings on the Defense Department's fiscal 2015 budget. The department plans to request funds for 34 F-35s, eight fewer than the 42 originally planned, according to officials. Six of those planes would be for the Marines.

"We consider this significant but by no means catastrophic," Frank Kendall, the Pentagon's undersecretary for acquisition, said in an emailed statement. While the program office is still performing an assessment, "based on preliminary analysis, a redesign" of some F-35B structures will be required, said Kendall, who has a master's degree in aerospace engineering.
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This plane has had a difficult time getting off the ground and now is having trouble staying in the air because of potential defects.  The delicate balance between strength and weight factors is still an issue.