More than 80 percent of the military’s F-35 joint strike fighters have been cleared and returned to flight status after the entire fleet was grounded last week due to a fuel tube issue, the Pentagon’s F-35 Joint Program Office said Monday.

Half of the remaining grounded jets among the 245 flown by the Air Force, Navy, and Marine Corps — about two dozen of aircraft — can be repaired with the military’s stock of replacement fuel tubes, according to the JPO.

The remaining jets are expected to be cleared for flight “in the coming weeks,” it said.

“More than 1,500 suppliers are on the F-35 program and this is an isolated incident which is quickly being addressed and fixed,” the program office said in a statement. “Safety is our primary goal, and we will continue to take every measure to ensure safe operations while we execute our mission.”

The JPO announced the global grounding on Thursday while the tubes in the fifth-generation aircrafts’ engine, made by Pratt & Whitney, were inspected for a defect. The F-35 is generally considered the world’s most advanced fighter jet and known as history’s most expensive Pentagon weapons program.

“If an engine had a suspect fuel tube installed, the part would be removed and replaced. If the engine had a known good fuel tube installed, then the aircraft could return to flight status,” the JPO said about the inspections.

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