All F-35s at Luke Air Force Base have been grounded, after officials with the Air Force said several pilots reported a lack of oxygen while flying.
Fice pilots have reportedly experienced symptoms since May 2, which includes dizziness, disorientation, and possibly tingling in the finger.
Major Becky Heyse with the Air Force said the the symptoms point to Hypoxia, a condition where someone was not getting enough oxygen. The pilots were forced to use a back up oxygen system, and were able to land safely.
Five incidents were just too alarming for top officials at Luke Air Force Base, who put a hold on all of the training flights until things are figured out.
"It can be fatal," said Maj. Heyse. "Luckily, all of our pilots are extremely well trained. Like I said, they are trained to know what these symptoms feel, and and they're trained to know what to when they feel these."
As pilots are reminded of procedures, The Pentagon has set up an action team to look into the issue. The team is made up of engineers, maintenance personnel and aeronautical physiologists, and they are digging into the root data to try and figure out what the root cause is."
Training flights could resume on Monday.