NATIONAL HARBOR, Md. — The head of the F-35 program office acknowledged Wednesday that the program will eventually transition from a centralized management structure to separate offices led by the U.S. Air Force, Navy and Marine Corps — backing up a directive by the Pentagon’s top acquisition official.

Speaking to a standing room only crowd on the final day of the Navy League’s Sea Air Space expo, Vice Adm. Mat Winter appeared to be broadly supportive of a memo issued by Ellen Lord, undersecretary of defense for acquisition and sustainment, which laid out near-term actions for the services and F-35 joint program office to prepare the way for a decentralized F-35 program.

“As we look forward, every weapon system in the United States at some point has changed its program office management structure to reflect the realities of the program phase,” Winter said.

“The migration of the program office, the appropriate skill sets, the organizational alignment and how we will execute that will continue to mature and be assessed every year. That’s the direction I’ve been given. That’s what the cover memo intent is and that’s what we’re executing today.”

The big outstanding question is when such a split will and should occur. While Lord’s March 27 letter to Congress doesn’t provide any specific information except to say that the “department will evaluate the right time to begin this transition,” the expectation within the Pentagon is that it could begin in a matter of years.

In his comments on Thursday, Winter struck a careful balance, saying that Lord “took the time to engage with the services and the JPO,” and that her guidance will ensure that “the JPO management will continue to be most efficient and effective to design, deliver, produce and sustain the F-35 air system into the future.”

However, he also noted that the F-35 program is unlike any other and hinted that it would be unwise to prematurely split the program.

“We will be in full sprint in development, production and sustainment for the next 20 years. Development will continue as a continuous improvement,” he said. “Production will eventually tail off some time, but we will sustain this system until the last flight of an F-35 occurs.”

In her letter, Lord spelled out a list of actions that could impact the makeup of the JPO, including a Pentagon review of its charter and audit of its billet structure.

Winter on Wednesday said many of those directives are already in process.

“The infamous cover memo that has specific areas of direction and pursuit that the program and that the partnership and that the Department of Defense will pursue is underway,” he said. “The majority of those elements are either incorporated or being incorporated because they make sense.”

For example, the JPO has already named variant leads to ensure that engineering, testing and logistics for the the F-35A conventional takeoff and landing model, the F-35B short takeoff and landing variant, and the F-35C carrier version are all aligned.

It also has service-specific program deputies, another of Lord’s mandates, he said.