The United States temporarily suspended operations for its fleet of F-35 fighter jets for 24 to 48 hours to check for possible faulty fuel tubes in the engines of the planes, after a crash in South Carolina late last month raised concerns about whether the parts were to blame.
The Pentagon said in a statement Thursday that the U.S. military and its international partners, which have also purchased F-35 fighter jets from contractor Lockheed Martin, would be suspending flight operations to inspect the fuel tubes out of caution.
"If suspect fuel tubes are installed, the part will be removed and replaced," the Pentagon said in a statement. "If known good fuel tubes are already installed, then those aircraft will be returned to flight status. Inspections are expected to be completed within the next 24 to 48 hours."
According to the Pentagon, the decision to temporarily suspend operations for the fleet results from initial data that investigators gathered in their probe of last month's crash.
During the incident, a Marine Corps variant of the F-35 joint-strike fighter, known as the F-35B, went down in the vicinity of Marine Corps Air Station Beaufort. The pilot ejected safely.
The accident marked the first crash of an F-35 in the 17 years since Lockheed Martin won the competition for the fighter jet in October 2001 and teamed with other contractors to begin production of the high-profile plane.
The fighter jet has experienced other issues over the years, including concerns about pilots receiving enough oxygen while flying and engine fires on the ground. But last month's incident was the first time the plane had crashed during flight.
"The primary goal following any mishap is the prevention of future incidents," the Pentagon statement added. "We will take every measure to ensure safe operations while we deliver, sustain and modernize the F-35 for the warfighter and our defense partners."
It was not immediately clear how many aircraft were affected. U.S. officials said the suspension would apply only to those F-35s with a certain kind of fuel tube, which one official estimated at roughly half the fleet.
The United States and foreign nations who have bought the joint-strike fighter are currently flying more than 340 of the jets, but plan to purchase thousands of the planes in the coming years.
The F-35 has attracted attention not only for its capabilities but also for its cost, after delays and overruns helped make the fighter-jet program the most expensive in the Pentagon's history.
Last month, the Pentagon announced that the latest batch of F-35s would cost the military $89 million per unit for the most common variant - the first time the plane's price tag had dropped below $90 million. The more complex Navy and Marine Corps variants of the plane remained above $100 million.
The high cost of the fighter jet attracted the attention of President Donald Trump in the month before he entered office and prompted him to suggest he would scrap the plane in favor of a different one from Boeing. The military, however, has stuck with production of the joint-strike fighter.
Trump has taken personal responsibility for driving down the cost of the F-35 fighter jet program by $600 to $700 million, but the Pentagon had already targeted per-unit cost reductions in that range over the lifetime of the program.