The F135 engine program for the F-35 Lightning II fighter has come under sharp criticism from two U.S. government entities over quality control and reliability issues. Engine manufacturer Pratt & Whitney and the Pentagon's F-35 Joint Program Office (JPO) challenged some of the findings and defended the program.  

A “Quality Assurance Inspection” the Department of Defense Inspector General (IG) released on April 27 identified 61 “nonconformities,” or violations, of quality management regulations and requirements. It recommended that the JPO coordinate with the Defense Contract Management Agency to implement corrective actions for those violations, and called for tighter program management overall. The JPO did not ensure that Pratt & Whitney “proactively identified, elevated, tracked and managed” F135 program risks; did not ensure that its supplier selection and management of underperforming suppliers were sufficient; and did not ensure that its software quality management practices were adequate, the IG found.

In a statement, the JPO acknowledged that the IG’s report is “factually accurate.” But it disagreed with three of six findings relating to the need for additional F135 program management oversight, risk management practices and software quality management practices. “In these three cases, the JPO believes the DOD IG findings and recommendations for corrective action are unnecessary, and, if implemented, would add cost and schedule growth to the program for items that are already well understood and carefully managed,” the JPO said.

Pratt & Whitney said that it has worked aggressively to implement corrective actions since the IG’s audit, which was conducted over two weeks in November at the manufacturer’s Connecticut facilities in Hartford and Middletown. As of earlier this month, it had implemented 60 percent of identified corrective actions, with the balance scheduled for completion by July.

“This was an audit of P&W's quality system and F135 contractual adherence, not an audit of F135 product quality,” the manufacturer stated. “None of these findings had any impact on the product performance. None of the findings has, or would have, affected the operational fleet, safety or mission capability of the aircraft or the F135 engine.”

On April 14, the Government Accountability Office (GAO) released a report on F-35 “affordability challenges” that described F135 engine reliability as “very poor” and dragging against the fighter’s overall reliability progress. Data Pratt & Whitney provided the agency indicated that the mean flight hours between failure of the engine used in the F-35A conventional takeoff and landing (CTOL) variant was at 21 percent of where it was expected to be at this point in the program; the engine for F-35B short takeoff and landing (STOVL) variant was at 52 percent.

“While overall reliability has increased, engine reliability over the last year has remained well below expected levels. Improving the F-35 engine reliability to achieve established goals will likely require more time and resources than originally planned,” the GAO stated.

Pratt & Whitney contested the GAO’s conclusions relating to reliability. “The report incorrectly assessed engine reliability, as it did not account for new designs that have been validated and are being incorporated into production and fleet engines,” the manufacturer said. The F135 CTOL engine exceeds its specification at 147 percent of requirements; the STOVL engine meets 119 percent of current requirements, it said.