F-35 engines from United Technologies Corp. 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 the reliability of engines from the company’s Pratt & Whitney unit is “very poor (less than half of what it should be) and has limited” progress for the F-35, the costliest U.S. weapons system, the watchdog agency said in a report sent to lawmakers this month.
The GAO cited the need to make design changes to the engines and then retrofit planes already built, along with continuing flaws in the plane’s software, in a report that warned the Defense Department’s “procurement plan may not be affordable.” The military plans to spend $391.1 billion for a fleet of 2,443 planes from prime contractor Lockheed Martin Corp.
The Pentagon’s inspector general issued a separate report Monday criticizing management of the engine program. 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.
Matthew Bates, a spokesman for Pratt & Whitney, said in an e-mail that the GAO “incorrectly assessed engine reliability, as it did not account for new designs that have been validated and are being incorporated.”
The Marine Corps model’s reliability “is at 71 percent of where it is expected to be” and “has made consistent improvement progress” since 2013, Bates said. He said the Air Force model’s engine “is at 147 percent of where it is expected at this point.”
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.”
Bennett Croswell, Pratt & Whitney’s president for military engines, told reporters Monday in Washington that it will take the company time to retrofit F-35s with planned reliability improvements and to accumulate actual flying hours “such that we’ll march up” the reliability curve, he said.
Croswell said he was surprised that the GAO called the engine’s reliability “very poor” when it’s meeting or exceeding its goals by the company’s metrics.
The Pentagon and Pratt & Whitney have funded initiatives since 2010 to improve engine reliability, Joe DellaVedova, a spokesman for the Defense Department’s F-35 program office, said in an e-mail. “Solutions have been developed and validated” and have already been incorporated, he said.
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.
Pratt & Whitney, the sole provider of F-35 engines, also has faced criticism from Pentagon officials for failing to reduce prices quickly enough and for lapses in quality.
The reliability issue may be reviewed by lawmakers as they weigh the Pentagon’s request for $1.2 billion to buy engines next year, up from $873 million this year, with annual funding rising to $2 billion by 2020.
Congress so far has approved at least $17 billion of a planned $67 billion for F-35 engines, with purchases to increase to 57 engines next year, from 38 this year, and 92 in 2020.
A House Armed Services Committee panel last week directed “an independent look at the engine program to make sure it is on the right track,” its chairman, Republican Representative Michael Turner of Ohio, said. The language is in the draft of the fiscal 2016 defense authorization bill that the full committee is scheduled to act on Wednesday.