In an abrupt reversal, Gov. Rendell yesterday abandoned plans to convert the soon-to-close Willow Grove Naval Air Station into a state-administered emergency and defense hub.

Rendell wrote to Secretary of Defense Robert Gates that because the military had declined to assign a flying mission to the Pennsylvania Air National Guard's 111th Fighter Wing at the base, the state could not justify spending millions of dollars to configure the airfield as a state-federal facility.

"The continued and increasing expenditures of scarce state resources on this project made no sense as long as the federal government failed to commit to being a full partner in this effort," Rendell wrote to Gates.

The decision likely ends a fight that Rendell began after Willow Grove turned up on the Defense Department's list of recommended base closings in 2005. Rather than see the 1,100-acre base shut down, Rendell proposed converting it into a nexus for the region's homeland security and other government needs, with outside agencies paying rent to the state to cover expenses.

Although the facility was expected to become fiscally self-sufficient eventually, the state estimated that it would have to spend up to $19 million on capital improvements and first-year operating costs, a sum Rendell now has called "an undue fiscal burden" during lean times.

"The concept is unsustainable without a corresponding federal pledge to support the installation and undertake military flights there," Rendell said in a statement.

Defense officials did not respond to calls for comment.

Although Rendell expressed hope that the base would house a proposed regional National Emergency Center, that prospect is uncertain. A House bill to create six such centers has not reached the committee level. Its only Pennsylvania cosponsor, Republican Rep. Jim Gerlach, did not return a call for comment.

State officials said they expected the Willow Grove Naval Air Station to be turned over to a redevelopment committee to handle its conversion to partial civilian use.

The committee is largely locally controlled. Thus, area residents who worried that the state-federal installation - and especially the private-sector businesses housed on it - would create incessant plane traffic probably will be restricting airstrip use themselves, officials said.

"This gives us more protection to making sure it's not used as a civilian airport," State Sen. Stewart J. Greenleaf (R., Montgomery) said.

About 110 acres of the base will continue to house Pennsylvania Air and Army National Guard units and an Army Reserve installation. But use of the military airstrip will end when the base's last A-10 jet fighters depart next summer.

The Navy base employs about 1,000 workers daily, and the post-shutdown units stationed there will put about 500 workers on site during weekdays, said Joan Nissley, spokeswoman for the state Department of Military and Veterans Affairs.

In April 2008, Rendell asked then-Secretary of the Navy Donald C. Winter to let the state use "all lands and facilities" at Willow Grove to "save the base as an important military installation."

Yesterday, in reversing the request, Rendell wrote to Gates that he hoped to maintain a "robust military enclave" even without the joint installation he had envisioned.

"It was a great idea," State Rep. Rick Taylor (D., Montgomery) said. "However, it succumbed to the economic realities that unless the federal government partnered, the funds would not be there. We wanted a flying mission for the 111th Fighter Wing out of there, and that's not in the cards."

Contact staff writer Derrick Nunnally at 610-313-8212 or dnunnally@phillynews.com.