A significant number of Lockheed Martin [LMT] F-35s in the U.S. and abroad, including the 33 in the Israeli Air Force, are undergoing inspections of the aircraft’s Martin-Baker Mk16-US16E ejection seats to determine whether the seats have enough explosive, magnesium powder in their cartridge actuated devices (CADs) to ensure the safety of pilots who punch out.

As of July 29, “over 90 percent of the inspections on Marine Corps ejection seat CADs were complete,” Navy Chief Petty Officer Matthew Olay, a spokesman for the F-35 Joint Program Office (JPO), wrote in an Aug. 1 email. “The Navy has completed inspections.  The Air Force’s inspections are ongoing. In general, the issue affected a relatively small number of seats. However, every seat matters. This issue is getting the highest priority.”

Nearly all of the 113 F-35As under Air Combat Command (ACC) at Joint Base Langley-Eustis, Va., are on a temporary stand-down, as the command examines relevant data on the CADs and performs inspections.

On July 19, ACC began a Time Compliance Technical Directive to inspect the CADs in the next three months, the command said. On July 29, ACC began the temporary stand-down “to expedite the inspection process,” per the command. “Based on data gathered from those inspections, ACC will make a determination to resume operations.”

ACC said that once an inspection clears a CAD on an aircraft, that aircraft will be able to resume flying.

Olay, the F-35 JPO spokesman, wrote in his Aug. 1 email that “there are F-35s cleared for flying.”

“To date, operations have been continuing with little to no impact from the seat cartridge issue,” he wrote.

The CAD defect surfaced during routine maintenance of an F-35A ejection seat at Hill AFB, Utah in April. It appears that the lack of sufficient magnesium powder in the CADs is rare and that loose CADs on some ejection seats may have led to the seats losing the powder.

The Cartridge Actuated Device/Propellant Actuated Device (CAD/PAD) Joint Program Office at the Naval Surface Warfare Center Indian Head Division in Maryland supplies the U.S. military with the devices for ejection seats.

Last week, the U.S. Navy and Marine Corps said that Martin-Baker had notified the services of potentially defective CADs on Boeing [BA] F/A-18B/C/D Hornets and F/A-18E/F Super Hornets, EA-18G Growlers, T-45 Goshawks and Northrop Grumman [NOC] F-5 Tiger II trainers (Defense Daily, July 28). The Department of the Navy said that it has used “validated radiography procedures” to scan on-hand inventory to verify replacement CAD parts were made correctly before starting to send them out to the fleet. If not, the department said that it is replacing the CAD.

While Naval Air Systems Command did not say how long the replacement process will take overall, the command said that it takes several hours to install and ready the replacement part per aircraft.