By Andrea Shalal
WASHINGTON (Reuters) - Mandatory engine inspections are now required every 13 hours for Lockheed Martin Corp's F-35 fighter jets, a significant easing of the three-hour requirement imposed after an engine failure in June temporarily grounded the entire fleet, a top Pentagon official said on Wednesday.
U.S. Rear Admiral Randy Mahr, the Pentagon's F-35 deputy program manager, said that all of the F-35 jets used for testing were now flying the required "full envelope" of speed and other flight maneuvers.
Separately, a spokesman for the F-35 jet program said certain restrictions remain in place for operational F-35s flown by the Marine Corps, Air Force and Navy, but those are not related to the June 23 engine incident and reflect the fact that the jets are still in developmental testing.
Mahr told reporters after a defense logistics conference that the F-35 jets were showing improved reliability, and said the program office expected a drop of about 15 percent in its estimate of the overall cost to operate and maintain the U.S. F-35 fleet over the next five decades.
The Pentagon in April forecast that it would cost $1.02 trillion to operate and maintain the U.S. F-35 fleet over the next 54 years, including inflation, a drop of 9 percent from a previous projection. At the time, the F-35 program office said it felt the cost was closer to $917 billion, given improving reliability.
Lorraine Martin, Lockheed's F-35 program manager, told reporters at the conference that her company was committed to lowering that so-called sustainment cost by 30 percent over that time period. As part of that drive, Lockheed has looked at every part that is proving less reliable than expected and is redesigning some, and changing processes in other cases.
Martin said there were now 120 F-35 jets flying at seven military bases, and the F-35 had logged more than 23,000 flying hours.
Bruce Tanner, Lockheed's chief financial officer, told an investor conference in New York hosted by Credit Suisse that the F-35 program was doing well, and production of the jets was expected to triple over the next four years.
He also said the Obama administration was widely expected to submit a fiscal 2016 budget request that exceeded the levels set in the Budget Control Act of 2011, but no details had yet been released.
(Editing by G Crosse and Matthew Lewis)