NATIONAL HARBOR, Md. — The JSTARS request for proposals (RFP) has been delayed as the US Air Force works with Congress to scrub language in the defense authorization bill that would force the service to pursue a fixed-price contract, the service's acquisition executive said.

Despite industry expectations that the Air Force would release its final RFP for the Joint Surveillance Target Attack Radar System recap program in September, the service instead put forward another draft version.

The reason, according to the service's head of acquisition, Darlene Costello, is that the Senate Armed Services Committee's version of the defense authorization contains a provision stipulating that it use a fixed-price contract.

"We are ready to release it, but there is language that says it must be a fixed-price contract in the SASC language," Costello said Wednesday at the Air Force Association's annual conference. "So we've been having conversations with the staff. We would like to have that worked out and so that is what we're waiting for."

The Air Force currently uses a "hybrid" approach during the engineering, manufacturing and development (EMD) stage of the program, meaning that it includes both fixed-price and cost-plus elements, she said.

"The fixed-price portions are most of it," she said. "A generic statement saying it must be a firm, fixed-price contract for EMD is a challenge for us."

If the service is forced to change its hybrid strategy, that would delay the RFP by three to six months. But because that pushes that release into a new fiscal year, it would likely add about a year to the planned initial operating capability (IOC) date, she said.

Although the congressional defense committees have been supportive of accelerating the IOC date, SASC chairman John McCain, R-Ariz., has been a steadfast opponent of cost-plus contracts where the government bears the burden of cost overruns.

Ultimately the service plans to procure 17 new aircraft, which will conduct the ground surveillance mission accomplished by the current JSTARS fleet that is nearing the end of its service life. It is expected to award an engineering, manufacturing and design contract to one of three competitors — Lockheed Martin, Boeing or incumbent Northrop Grumman — in fiscal 2018.

Lt. Gen. Arnold Bunch, the service’s top uniformed acquisition official, declined to speculate on when the RFP would ultimately be released, stating that he would get it out "as soon as we can."

"We’ve had a very healthy dialogue with the Hill so far," he said. "And we continue to try to work to resolve that."