Engines being built for Lockheed Martin’s F-35 fighter jet are proving so unreliable that U.S. plans to increase production of the fighter jet may be slowed, according to congressional auditors.
Data from flight tests evaluated by the Government Accountability Office show that the reliability of engines made by Pratt & Whitney, a unit of United Technologies, is “very poor (less than half of what it should be) and has limited” progress for the F-35, the watchdog agency said in a report sent to lawmakers this month.
The agency cited the need to make design changes in the engines and then retrofit planes already built, along with continuing flaws in the plane’s software, and warned that the Defense Department’s “procurement plan may not be affordable.” The military plans to spend $391.1 billion for 2,443 jets. The F-35 is being assembled at Lockheed Martin Aeronautics in west Fort Worth.
The Pentagon inspector general also criticized management of the engine program in another report released Monday. It identified 61 “noncomformities” with Defense Department requirements and policies and called for the Pentagon office in charge of the F-35 to establish new quality goals and provide more oversight.
As of late December, engines on the Marine Corps’ complex version of the F-35, designed for short takeoffs and vertical landings, flew about 47 hours between failures caused by engine design issues instead of the 90 hours planned for this point, according to GAO officials. Air Force and Navy model engines flew about 25 hours between failures instead of the 120 hours planned.
Pratt & Whitney provided the data “underpinning the engine reliability percentages in our report,” Michael Sullivan, a GAO director for acquisition who oversees its F-35 work, said in an e-mail.
Pratt & Whitney spokesman Matthew Bates said in an e-mail that the agency “incorrectly assessed engine reliability, as it did not account for new designs that have been validated and are being incorporated.”
The agency “has confused engine spec reliability and aircraft spec reliability, which are measured differently,” he said. “While the report lists some propulsion concerns,” the Pentagon has “validated our reliability performance.”
Sullivan of the GAO said Pratt & Whitney’s figures “include design changes that are validated and are now being incorporated into the engine, but have not yet been demonstrated through flight testing.”
The Pentagon and Pratt & Whitney have funded initiatives since 2010 to improve engine reliability, said Joe DellaVedova, a spokesman for the Defense Department’s F-35 program office. “Solutions have been developed and validated” and have already been incorporated, he said in an email.
While the fixes will provide the desired reliability for the Air Force and Navy versions, the Marine Corps’ F-35 “is projected to be slightly below specification requirements,” he said. The contractor and the program office are “adding reliability redesign projects,” he said.