F-35 Cost Rises 10% to $485 Billion to Fix Overheating Engines

The Pentagon’s cost to develop and produce Lockheed Martin Corp.’s F-35 has risen almost 10% to about $485 billion now that money needed for engine improvements has been included in the official estimate for the costliest US weapons system.

The previous $442 billion estimate for the fighter jet was changed officially earlier this year, but that wasn’t disclosed until the Defense Department’s latest Selected Acquisition Report assessing the program was posted online recently.

The majority of the increase stems from the expected costs for the upgrade of the plane’s engine core and improvements to its “power thermal management,” which ...