Government auditors say the cost of the Defense Department's F-35 fighter jet program dropped 3 percent to $332 billion in the past year.
The Government Accountability Office, known as the investigative arm of Congress, said the estimated cost of the Joint Strike Fighter program -- the Pentagon's most expensive acquisition effort -- is $11.5 billion less than what it was a year ago.
While that only amounts to a 3.4 percent annual change in program cost, it was the biggest year-over-year decrease in dollar terms of any program, the office said.
"The most significant of these decreases is the $11.5 billion reduction to the F-35 Joint Strike Fighter program's estimate, due solely to efficiencies found within the program as no decrease in quantities was reported," according to the GAO's annual assessment of major defense programs.
The Pentagon, which maintains separate cost estimates for the program, plans to buy a total of 2,457 of the stealth fighters made by Lockheed Martin Corp. to replace such aircraft as the F-16, A-10, F/A-18 and AV-8B. The F-35's engine is made by United Technologies Corp.'s Pratt & Whitney unit.
While the GAO's latest cost figures are likely to please proponents of the program, they're still significantly higher than initial estimates.
The overall cost to develop and buy the Lightning IIs is almost 50 percent higher than the initial estimate of $225 billion, according to the document, which uses fiscal 2014 dollars. In addition, the costs have increased despite a 14-percent reduction in the planned quantity from 2,866 aircraft to 2,457 aircraft, it states.
What's more, the cost to operate and support the aircraft is estimated at more than $1 trillion over its lifetime, the GAO reported.
Through last year, the Pentagon has spent about $35 billion on 150 F-35s, according to the document. The department is expected to spend, on average, about $12 billion a year on the acquisition effort, it states.
At this point, a handful of critical technologies "are not mature and the program continues to experience design changes," just a quarter of its critical manufacturing processes can consistently produce quality parts, fewer planes were produced in 2013 than initially planned and lingering software issues threaten to delay when the aircraft will be ready for combat operations, according to the report.
The Marine Corps previously planned to begin operational flights of the F-35 fighter jet in 2015, followed by the Air Force in 2016 and the Navy in 2019.
Associate Editor Brendan McGarry can be reached at firstname.lastname@example.org.