Defense Department officials are gauging the potential for leveraging two engine makers' adaptive propulsion system offerings into a "tri-variant" solution that would be viable across the F-35 Joint Strike Fighter fleet. Through a military-funded effort, General Electric and Pratt & Whitney are drawing from their work tied to the Air Force’s Adaptive Engine Transition Program to “augment” a broader business case assessment that will review proposed engine, power and thermal management system modernization options, an F-35 Joint Program Office spokesman...