The Pentagon on Thursday said its fleet of Lockheed Martin Corp.
"F-35 flight trials from the aircraft carrier, HMS Queen Elizabeth, are continuing and the programme remains on schedule to provide our armed forces with a game-changing capability".
The stand down affects more than 200 jets while an "inspection of a fuel tube" in F-35 engines takes place, according to a Pentagon spokesman.
At Marine Corps Air Station Beaufort in SC, both British and American pilots are learning how to fly the F-35B.
Less than two weeks ago, two U.S. Marine Corps F-35Bs flew the first American combat missions for the new joint strike fighter.
Inspections were expected to be completed within 24 to 48 hours.
According to the Marine Corps Times, "investigators. suspect there is a widespread problem with the advanced fighter's fuel tubes". There are more than 340 F-35s being used now by the United States and other countries.
The F-35 joint strike fighter is the most expensive program in the Pentagon's history.
The South Carolina crash came only one day after the U.S. military first used the F-35 in combat, when Marine Corps fighters hit Taliban targets in Afghanistan.
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The Joint Program Office statement included "international partners" in the flight operation grounding, though the United Kingdom's Ministry of Defence tweeted they have only "paused some F-35 flying as a precautionary measure while we consider the findings of an ongoing enquiry".
Now the USA military has purchased 245 aircraft from Lockheed Martin.
The DOD said in the statement that if "good fuel tubes are already installed, then those aircraft will be returned to flight status".
The inspections come in the wake of an F-35B jet crash outside of Beaufort, S.C. on September 28. This allows the plane to hover and land vertically like a helicopter and is a critical requirement for the Marine Corps, which often operates from amphibious ships with smaller decks than the Navy's aircraft carriers.
All three services have stopped flying the F-35 while fuel tubes in the aircraft are inspected and replaced if necessary. The program is estimated to have a lifetime cost of over $1.5 trillion.
Of the 280 operational F-35s purchased to date by USA and global partners, only 51 percent are now available for flight, Vice Adm. The Air Force has 156, the Marine Corps has 61 and the Navy has 28.
Because the problem is related to a fleetwide engine issue, rather than just in the F-35B models, it appears unlikely that the problem is unrelated to the short-takeoff and vertical-landing capabilities of the Marine's design.
This story is developing and will be updated.