By Marina Malenic

The Pentagon’s top weapons buyer yesterday told key allies set to purchase early production copies of the F-35 Joint Strike Fighter that “two years of disappointing performance” for the development effort will be quelled by a program restructure and pending leadership changes.

“I was able to report to the international partners today that we now have a realistic program plan and…not a blindly optimistic one,” Ashton Carter, the Undersecretary of Defense for acquisition, technology and logistics.

Carter was speaking during a teleconference with reporters following the annual F-35 CEO conference in Fort Worth, Texas, where prime contractor Lockheed Martin [LMT] builds the airplanes.

The company is developing three F-35 models to replace 13 types of tactical aircraft for the United States Air Force, Marine Corps and Navy. Australia, Canada, Denmark, Italy, the Netherlands, Norway, Turkey and the United Kingdom are participating in the effort and are set to purchase aircraft in the coming years.

Carter said the government is in the process of making “aggressive management changes'” in the Joint Program Office in the Pentagon that manages the effort, primarily by elevating the military program manager position to a three-star rank. Defense Secretary Robert Gates last month announced the dismissal of Marine Maj. Gen. David Heinz from the post. His replacement has not yet been announced.

Lockheed Martin Chairman and CEO Robert Stevens, asked whether his company will also make leadership changes, said that “the subject of accountability comes up with appropriate frequency here” and that he has “replaced some people.” However, he expressed confidence in company Vice President and F-35 program manager Dan Crowley.

“I have no desire to remove him,” Stevens said.

Earlier this week, the Pentagon’s comptroller warned that any further cost growth in the program will result in cuts to the number of aircraft the department is able to purchase. Undersecretary of Defense Robert Hale, the department’s chief financial officer, said that future cost growth is not out of the question.

Late last year, the Pentagon acknowledged that its special assessment team once again found that the F-35 program is at risk of significant cost increases. The Joint Estimating Team’s latest cost projection for the program contains similar numbers to last year’s JET estimate. Both warn that the $300 billion program may end up costing the government some $16.6 billion more than budgeted.

Carter yesterday once again acknowledged the problems.

“This schedule and cost trend was unacceptable for the taxpayers of the United States and, I think, the other eight nations here,” he said.

The Pentagon’s program of record has until recently called for 2,456 of the fighters in three variants for the Air Force, Navy and Marine Corps. Last week, Carter authorized a program restructure that reduces that number by 122 aircraft in the near term. A 13-month extension of the development phase of the program was also authorized.

And while the Pentagon is ramping down the buy rate in the near term, Carter said officials are “giving industry every opportunity to build as many aircraft as possible.”

Stevens said that Lockheed Martin wants to “earn back” those numbers by reducing costs. He said that there are signs that certain “stress points,” such as parts shortages, are now showing signs of improvement.