F-35 Joint Strike Fighter, Problems Completing Software Testing May Hinder Delivery of Expected Warfighting Capabilities

" The F-35 Lightning II, also known as the Joint Strike Fighter, is DOD's most costly and ambitious acquisition program. The program seeks to develop and field three aircraft variants for the Air Force, Navy, and Marine Corps and eight international partners. The F-35 is integral to U.S. and international plans to replace existing fighter aircraft and support future combat operations. Total U.S. planned investment in the F-35 program is approaching $400 billion to develop and acquire 2,457 aircraft through 2037, plus hundreds of billions of dollars in long-term spending to operate and maintain the aircraft. The National Defense Authorization Act for Fiscal Year 2010 mandated that GAO review the F-35 acquisition program annually for 6 years. In this, GAO's fifth annual report on the F-35, GAO assesses the program's (1) ongoing development and testing, (2) long-term affordability, and (3) manufacturing progress. GAO reviewed and analyzed manufacturing data through December 2013, program test plans, and internal DOD analyses, and spoke with DOD, program, and contractor officials. "