While the F-35 fighter’s prime contractor Lockheed Martin touts the “blueprint for affordability” that since last year has helped it shave costs from its manufacturing processes, engine supplier Pratt & Whitney has waged its own “war on cost” since 2009. From the time it built the sixth flight-test powerplant to those it is producing today, the engine manufacturer claims to have reduced the cost of the F135 turbofan by 55 percent.

In April, the F135 incurred strong criticism from two U.S. government entities over quality control and reliability issues. A “quality assurance inspection” released by the Department of Defense (DOD) Inspector General (IG) on April 27 identified 61 “nonconformities,” or violations, of quality management regulations and requirements. Two week earlier, on April 14, the Government Accountability Office (GAO) released a report on F-35 “affordability challenges” that described F135 reliability as “very poor” and dragging against the fighter’s overall reliability progress. Both Pratt & Whitney and the Pentagon's F-35 Joint Program Office (JPO) challenged some of the findings and defended the program (see below).  

The manufacturer tracks its progress on a cost curve that starts with the sixth flight-test engine, or FTE-6, as the baseline. “We have a curve that defines how our price will change unit by unit up through the 300th unit. It’s a prescribed cost reduction,” said Mark Buongiorno, Pratt & Whitney F135 program vice president, during a recent press briefing in April. “We identify specific tasks, we work those tasks to closure and validate the changes to make sure they meet the engineering intent of the product.”

As of March 31, Pratt & Whitney had delivered 217 F135 engines to Lockheed Martin in Fort Worth and to the Cameri Final Assembly and Check-Out facility west of Milan, Italy, which is assembling F-35s for that country and the Netherlands. While it has committed to the JPO to deliver the F135 based on the cost curve, the manufacturer is not currently tracking exactly to the curve in building the engine, acknowledged Buongiorno, who was appointed program vice president in February.

Pratt & Whitney’s goal by the 300th engine is to match the price of the F119-PW-100 turbofan that powers the F-22 Raptor, from which the F135 engine is derived. It notes that the F135 is 20 percent larger than the F119. Around October, the company hopes to sign a contract covering the LRIP 9 batch of 60 engines and the LRIP 10 batch of 100 engines.

The F-35 program selected acquisition report (SAR) the DOD released in March estimates the overall cost of the F135 engine subprogram will decline by $1.6 billion–or 2.3 percent–to $67 billion. The Pentagon attributed this to revised inflation estimates, reductions in initial spares requirements due to the maturation of the engine and revised estimates based on actual costs of early LRIP lots.

Correction Action

The IG in April 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. According to the IG report, 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 was “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. As of early April, it had implemented 60 percent of identified corrective actions, with the balance scheduled for completion by July.

Data Pratt & Whitney provided the GAO 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.