Pentagon authorizes F-35 to fly with beams after years of suspension.
The approval ends an ironic episode for the fighter nicknamed the “Lightning II.”

The Pentagon has lifted thunderstorm restrictions for the most widely used version of the F-35 Joint Strike Fighter, allowing the Lockheed Martin aircraft to fly in thunderstorms for the first time since 2020.

The Defense Department formally lifted the restrictions on March 19 after devising a hardware and software fix for the lightning protection system used aboard the F-35A conventional takeoff and landing variant, JPO spokesman Russ Goemaere said. in response to a press query.

The F-35A has been prohibited from flying within 25 miles of lightning proximity since June 2020, when damaged tubes installed in the Onboard Inert Gas Generation System (OBIGGS) were found on several aircraft.

OBIGGS prevents a plane from exploding when struck by lightning by pumping nitrogen-enriched air into the fuel tanks to inert their contents, and damage to the tubes carrying the inert gas raised fears that the system would not function properly if of emergency.

The JPO declined to comment on how many F-35As have been modified with the latest OBIGGS fix and cleared to fly near lighting, citing operational safety concerns.

“The fix included a more robust Onboard Inert Gas Generation System (OBIGGS) hardware design and software updates. The testing of these efforts was a combination of laboratory and flight testing,” Goemaere said.

The Air Force’s Air Combat Command said in a statement that the OBIGGS “underwent extensive testing and hardware analysis” and “once it was certified safe to operate, the distance restriction was reduced.”

Lightning has long been an ironic thorn in the side of the F-35, nicknamed Lightning II.

In the early 2010s, the Pentagon imposed flight restrictions on the F-35 after its independent weapons tester found that the fuel tanks were not receiving enough nitrogen-enriched gas to make them safe. After redesigning OBIGGS, the program office cleared the F-35 to fly near lightning in 2014.

Six years later, maintenance personnel at the Ogden Logistics Complex at Hill Air Force Base, Utah, discovered the latest problem with the OBIGGS tubes during routine depot maintenance, finding more than a dozen F-35As with damaged tubes during an initial inspection of 24 reactors.

The problem – which was not discovered in the short takeoff and landing F-35B or carrier-based F-35C variants – prompted the Pentagon to temporarily suspend all F-35 deliveries for a couple of weeks in 2020 to rule out a manufacturing defect. OBIGGS production. Deliveries resumed after Lockheed validated that it was installing the system correctly, with issues later developing after operational use, a Lockheed spokesperson said at the time.

The JPO hoped to authorize the F-35 to operate under illuminated conditions in 2022 after making initial hardware and software adjustments to OBIGGS, but deemed the planned improvements insufficient to resolve safety concerns, officials said at the time.

The JPO then said it did not have a timetable for the implementation of an additional correction that would allow it to lift the restrictions. However, the program office would continue to re-equip the Air Force’s F-35A fleet with the OBIGGS modifications, which included more robust tubes and fittings that could better withstand flight vibrations, as well as software that notifies the pilot if the performance of the OBIGGS is deteriorating.

The JPO declined to detail how the latest OBIGGS updates improved on previous attempts, citing operational security reasons.

“We thank the Government and industry engineers who applied technical rigor, performed analysis, and drove data-driven decision-making to overcome the challenges identified in 2022,” Goemaere said. “The solution restores operational capability while providing additional safety for pilots and aircraft.”

In its statement, Air Combat Command added that pilots are instructed to never fly directly into lightning conditions unless storm penetration is necessary to accomplish a mission.

Valerie Insinna