Following the Oct. 11 grounding of all F-35 Joint Strike Fighters due to a failed fuel tube in some aircraft, two additional fuel supply tubes have been identified as suspect and require inspection, the Pentagon’s joint program office said Oct. 25.

“While the two additional fuel tubes have not failed, engineering data collected during the ongoing investigation established the requirement for a time-phased inspection based on engine flight hours,” said Joe DellaVedova, F-35 JPO spokesman, in an emailed statement Thursday. “The inspection maintains F-35 fleet safety standards as older engines may require fuel tube replacement.”

An F-35A lands at Eielson Air Force Base in Alaska for cold-weather testing. (Air Force photo)
An F-35A lands at Eielson Air Force Base in Alaska for cold-weather testing. (Air Force photo)

The inspection process and replacement of parts can be done by flightline maintenance and does not require removing the engine, he added. Replacements can be completed in less than 48 hours when a part is available, and engine manufacturer Pratt & Whitney [UTX] is ramping up supply, he said.

F-35 aircraft that did not possess the suspect parts continue to operate, but “the exact number of engines that may require replacement fuel tubes speaks to operational security and readiness status of the fleet, and will not be released by the JPO,” DellaVedova said.

These inspections come as the Defense Department and F-35 manufacturer Lockheed Martin [LMT] continue to investigate the cause of a September F-35B crash in South Carolina (Defense Daily, Oct. 11).