The world’s most advanced F-35 II Lightning fighter jet has just been grounded in the US Air Force (USAF), the Navy (USN), and Marine Corps (USMC) as well. But, before this, a report about its faulty mechanism had been reported and pushed aside.

The issue around the ejection seats of the F-35 had been reported back in April when a routine maintenance inspection at Hill FB discovered an anomaly with one of the Seat Cartridge Actuated Device (CAD). According to a spokesperson for Martin-Baker, Steve Roberts, the issue was traced back to the gap in the manufacturing process, “which was addressed and changed.”

Lockheed Martin’s F-35s can reach the speed of Mach 1.6 (1,200 mph) and a P135-PW-100 — 40,000 lb Max; 25,000 lb Mil propulsion. This is a single-seat, single-engine aircraft with three versions for the US Navy, US Air Force, and similar versions for the US Marine Corps and the UK Royal Air Force and Royal Navy.

The F-35 is known for its advanced sensor package, which gathers information in real-time, giving pilots the ultimate advantage during flights.

“Its tremendous processing power, open architecture, sophisticated sensors, information fusion and flexible communication links make the F-35 an indispensable tool in future homeland defense, joint and coalition irregular warfare, and major combat operations,” according to Military.

Aside from its technological features, the F-35 is the only known operational fighter jet with vertical take-off and landing (VTOL) capabilities, making it a top asset for naval operations.

The initial report in April noted the investigators still couldn’t analyze the scale of the issue. However, when the US Air Combat Command (ACC) stepped in and conducted their inspection, they found an apparent problem with the seat ejection. Then, on July 19, within 15 days of ACC inspection, the ACC and Air Education and Training Command grounded their F-35s for a wide-scale investigation. They will proceed with their 90-day inspection in the coming months.

Around 2,700 ejection seat cartridges were inspected, and only three erratic ones were found. Martin-Baker has been cooperative during the inspection.

ACC Spokesperson Alexi Worley said in an interview that the initial reports only covered a selection of ejector seat cartridges. Still, they immediately discovered more alarming issues traced to the production line.

Because of the innate root of the issue, they recommend that other military spheres outside the US halt the use of the F-35s until the investigation has been completed. Martin-Baker provides the military with essential data during this investigative period as a band-aid solution.

“This issue was found to be unique to this particular CAD part number and unique to the F-35, Martin-Baker has been providing the primes and multiple Govt agencies with supporting data to prove that all other aircraft may be excluded,” said Steve Roberts, spokesperson for Martin-Baker. “Outside the F-35, not a single anomaly has been discovered worldwide as a result of the forensic investigation which continues at pace.”

Aside from the F-35s, the investigation also grounded a couple of F/A-18 Hornets, F/A-18E/F Super Hornets, EA-18G Growlers, F-5 Tiger II training aircraft, and T-45-Goshawk. There were also 300 T-38 Talon and T-6 Texan II training planes grounded during the third week of July, but they were greenlighted on July 28 after passing the inspection.

“Based on the known data at the time, the aircraft was deemed flyable with an acceptable level of risk,” Worley said in a statement. “As these inspections continued to take place, a higher number of suspect cartridges were found, leading ACC to stand down its fleet to conduct the remainder of the inspections.”

AETC is supporting ACC during the investigations. Spokesperson Capt. Lauren Woods said some F-35s had been cleared for flight, though.

As of writing, Worley could not confirm how many F-35s abroad are affected by the issue, but as Maj. Gen. Craig Willis (19th Air Force Commander) has said in a statement that this temporary grounding is being done to ensure the safety of airmen.

“Our primary concern is the safety of our Airmen and it is imperative that they have confidence in our equipment,” he said. “Our actions today were taken out of an abundance of caution in order to ensure the safety of our pilots and aircrew. We will not return aircraft affected by this issue to the flying schedule until we’re confident their escape systems are fully functional.”

But, with multiple reports surrounding the supposedly reliable F-35, Defense Policy Fellow at the American Enterprise Institute Mackenzie Eaglen is doubtful of its capability and doubts if the seat issue is the only concern of the aircraft.

“I can say the F-35 is grounded too often, which impacts operations, readiness and our conventional deterrent,” Eaglen said.