WASHINGTON (Reuters) - The Pentagon said on Wednesday that no additional cracks have been found on F-35 fighter engines during inspections begun after the February 19 incident that has grounded the entire fighter fleet and halted operation of the engines on the ground.
Kyra Hawn, spokeswoman for the F-35 program office, said the investigation into the incident at Eglin Air Force Base in Florida was continuing, with engineers at enginemaker Pratt & Whitney due to break open the affected engine blade for further study on Wednesday.
Pratt, a unit of United Technologies Corp, supplies the engine for the single-engine, single-seat fighter plane, which is built by Lockheed Martin Corp.
The Pentagon announced the grounding of all F-35 warplanes on Friday after an inspection revealed a crack on a turbine blade in the jet engine of an F-35 being tested at Edwards Air Force Base in California.
It was the second engine-related grounding in two months of the $396 billion F-35 Joint Strike Fighter, the Pentagon's largest weapons program.
Hawn said inspections were under way of the engines on all 51 F-35 jets in the Pentagon's inventory, as well as additional engines that are spares or on planes being assembled by Lockheed at its Fort Worth, Texas, plant.
She said nondestructive testing of the cracked turbine blade had been completed, including microscopic tests and X-rays, with "destructive" testing to begin on Wednesday, including a test in which the blade will be "fractured" open for closer examination of the surface.
She said the Pentagon would announce further details when the engineering investigation was complete.
Sources familiar with the investigation told Reuters on Tuesday that Pratt & Whitney is 99 percent sure the fan blade problem that grounded the Pentagon's F-35 fleet was not caused by high-cycle fatigue, which could force a costly design change.
Lieutenant General Christopher Bogdan, who runs the F-35 program for the Pentagon, slammed Pratt and Lockheed during an air show in Australia earlier on Wednesday, accusing the companies of trying to "squeeze every nickel" out of the U.S. government and failing to see the long-term benefits of the project.
Hawn said a separate incident involving temperature control equipment built by Honeywell International Inc has been deemed a "minor test discovery, with no impact to safety of flight or operations.
(Reporting by Andrea Shalal-Esa; editing by Gerald E. McCormick; and Matthew Lewis)