WASHINGTON — The Defense Department has awarded Lockheed Martin a $5.6 billion undefinitized contract that will allow the company to continue work on the eleventh lot of F-35s.



The F-35 joint program office still intends wrap up negotiations on a final contract by the end of the year, but making an interim award was necessary because of "complex production lines and supply chain dynamics," JPO spokesman Joe DellaVedova said in an emailed statement to reporters.



The award immediately obligates a combined $4.49 billion from the U.S. Air Force, Navy and Marine Corps for work on 91 aircraft. A $2.28 billion payment to Lockheed from international customers is expected later this month for an additional 50 aircraft.



The JPO is also engaged in ongoing negotiations with Pratt & Whitney, which supplies the joint strike fighter's F135 engine, and plans to finalize a deal by the end of the year. The program office regularly issues separate contracts for the F-35 airframes and engines.



"Final aircraft prices for each customer's variant will be determined upon final negotiations targeted for the end of this year. We are confident that the final negotiated Lot 11 aircraft unit prices will be less than Lot 10," DellaVedova stated.



Lot 11 deliveries are anticipated to run from 2019 to 2020.



