WASHINGTON — Budget uncertainty may force the US Air Force to cancel a planned recapitalization of its ground surveillance fleet, according to a top service official.

"There is still a possibility given the budget that [the Joint Surveillance Target Attack Radar System] may not happen," William LaPlante, assistant secretary of the Air Force for acquisition, told reporters after an event hosted by Defense One on Tuesday.

"It's a budget issue, so it depends on the sequester and where the priorities are in the department," he said. "It might not happen at all."

Although LaPlante has previously alluded to the impact sequestration cuts or a yearlong continuing resolution could have on JSTARS, of sequestration cuts or year-long continuing resolution, these remarks pack a hefty punch in light of yet another delay to the program. The Pentagon last month denied JSTARS approval to move into the next phase of the acquisition cycle, Defense News first reported Sept. 29.

The Pentagon's Defense Acquisition Board reviewed the JSTARS program during a Sept. 18 meeting that was widely expected to approve a "Milestone A" decision to move into the technology maturation and risk reduction phase. But the Pentagon did not give the green light and instead sent the Air Force and industry partners back to complete additional work.

The Air Force has declined to specify what additional work needs to be done.

The service officially kicked off the competition to replace its aging E-8 JSTARS in early August, awarding a trio of competitors each a pre-engineering and manufacturing development contract for a total of $31.4 million. Northrop Grumman, which builds the existing aircraft, is teamed with Gulfstream and its G550 business jet, with L-3 helping with integration. Lockheed Martin is working with Bombardier on a proposal based on the Canadian company’s Global 6,000 business jet. Meanwhile, Boeing is offering a modified version of its 737-700 commercial airliner.

Industry widely expected a Milestone A decision, which would authorize additional contract money for system and platform demonstrations, at the end of September, with a downselect for the EMD award in the summer or early fall of 2017. The Air Force had initially planned to declare initial operational capability for JSTARS in fiscal 2022, but the latest budget proposal delayed that date to fiscal 2023.

Some say the Pentagon is purposefully delaying JSTARS due to internal debate over the path forward for the recapitalization. One analyst and defense industry consultant, Loren Thompson, suggested certain officials are pushing for an unmanned aircraft to replace the current JSTARS fleet.

But LaPlante insisted the delay is due to concern over potential sequestration cuts or a yearlong CR, a stopgap spending measure to fund the government at prior-year levels. If either scenario occurs, the Air Force may not have enough money to finish the recapitalization program.

"This is one of those programs that is a new start in a very difficult budget environment," LaPlante said during the event. "Given all of that, it's under a lot of scrutiny to make sure that if we do start it, we can afford it."

Twitter: @laraseligman