The F-35A Lightning II, the conventional takeoff and landing type of the F-35 joint strike fighter, has had substantial operational limits for several years due to issues with its Onboard inert Gas Generation System (OBIGGS). This essential mechanism is designed to inject nitrogen-enriched gas into the aircraft’s fuel tanks, preventing explosions in the case of a lightning strike. However, normal maintenance checks in 2020 found damaged tubes within the OBIGGS, raising doubt on its ability to work effectively. As a result, the Pentagon set restrictive flying limitations, preventing F-35A operations within 25 miles of any lightning activity.
For example, in August 2020, four F-35A fighter jets from the Royal Netherlands Air Force (Koninklijke Luchtmacht, KLu) were supposed to accompany a US Air Force B-52H Stratofortress strategic bomber over the Netherlands as part of Operation “Allied Sky,” which was intended as a “demonstration of solidarity” among NATO allies. However, the KLu aircraft were not allowed to take off because of the bad weather.
Only this variant of the F-35 was affected. There were no problems with the F-35C carrier-based version at the time. The F-35 B has a different OBIGGS design because of the Rolls-Royce LiftSystem, which allows it to land vertically.
This was not the first time the F-35A’s OBIGGS malfunctioned. In the early 2010s, it was found that it was not delivering enough nitrogen to the tanks. This compelled its manufacturer, Lockheed Martin, to develop a solution. However, when the fault was identified in 2020, the manufacturer indicated that it came from the “field.”
In November 2021, the F-35 Program Office reported that it was investigating a “hardware modification” that would replace a piece of the F-35A’s OBIGGS tubes and fittings with a “more robust design.” Then, in 2022, there was talk of installing a software upgrade to notify pilots of any potential deterioration of this system. However, the limits were not removed.
Finally, on March 19, the Pentagon decided to lift them. According to the Air Combat Command, as reported by Breaking Defense, the updated OBIGGS underwent a “thorough examination.” After it was “confirmed safe,” the limits were relaxed. Well, nearly… since F-35A pilots are told to “never fly in a rainstorm” unless absolutely necessary to fulfill their mission.
