Test Fault?

Hartford, Conn. It’s not a sure thing that Pratt & Whitney will have to pay to redesign a part on its Joint Strike Fighter F135 engine after a test failure late last year, company military engines president Bennett Croswell said. The part—called a “blisk,” because it is a single-piece disk with fan blades—failed last December during an accelerated stress test, when the test engine was at 77 percent of its design life. However, “we don’t know if there was any life shortfall,” and therefore it’s “premature” to discuss liability, Croswell said in an interview with Air Force Magazine at P&W’s Hartford, Conn., campus. During the accelerated mission tests, in which “we … put a lot of life on the engine in a short amount of time,” it was determined that some of the testing “was more strenuous” than the required performance, so the part may not have failed prematurely, Croswell said. Testing will be done later this year to determine if the part met the original specification. A new part was already being designed in the interest of lowering cost, and will be cut into production in a future run. The failure did not ground the fleet; it was determined not to pose a flight safety risk.