WASHINGTON (Sputnik) — Five F-35A pilots flying out of Luke Air Force Base in Arizona between May and early-June experienced oxygen deprivation symptoms, indicative of hypoxia, causing Leonard to halt flight operations in mid-June while Air Force experts and members of the F-35 Joint Program Executive Office examined each incident, the Air Force Times reported on Wednesday.
The pilots took back to the skies on June 21 but with a ban of flying the strike fighter above 25,000 feet, according to the report. That restriction was removed on Aug. 30
"We have learned a lot over the past two months, and while we have yet to identify a singular cause, we have reduced potential causes for labored breathing [and] carbon monoxide ingestion, and refined our procedures and training," Leonard was quoted as saying by the Air Force Times.
The F-35 Joint Strike Fighter is manufactured by Lockheed Martin and comes in three versions: The Air Force F-35A, the Marine Corps F-35B vertical takeoff and landing jet, and the Navy F-35C aircraft carrier fighter.