WASHINGTON, Oct. 19 (UPI) -- U.S. Air Force pilots weighing less than 136 pounds have been restricted from flying the F-35A Lightning II due to safety concerns.
The restriction, announced by the Secretary of the Air Force Public Affairs office, said the restriction is due to a safety concern over use of the plane's ejection seat.
"In a recent test, analysis identified an unacceptable risk of neck injury during parachute deployment/opening for lighter-weight pilots at low-speed conditions," the announcement said.
"Air Force leaders decided that as an interim solution, no pilot less than 136 pounds will be allowed to fly the aircraft until the problem is resolved. As a result, one pilot was impacted."
The Air Force added that there is an elevated risk of injury for pilots between 136 and 165 pounds ejecting at slow speed – an estimated 1 in 100,000 flight hours.
Pilots falling within the 136 to 165 pound weight range, however, will be allowed to fly the aircraft.
"We expect the manufacturer to find and implement a solution," said Secretary of the Air Force Deborah Lee James. "We must ensure the ejection seat is tested to meet our specifications and weight requirements. We are going to ensure this gets done right."
The F-35 Joint Program Office is working in concert with the contractors to explore possible options to fix the ejection seat issue.
Roll Call reported that all F-35 variants have ejection seats made by Martin-Baker Aircraft Co. Ltd. of Britain.
During an ejection from the F-35, the pilot's canopy is shattered by an explosive charge, then the entire seat is propelled skyward. Tests this summer showed that the lightest F-35 pilots are more likely to be rotated into a position in which they face injury from the parachute rocketing into their heads when the plane is flying low and relatively slowly, Roll Call reported.
According to documents obtained by the publication, for "F-35 pilots weighing 135 pounds or less, there is a 98 percent 'probability of fatal injury' during ejections from the jet at 160 knots, a typical speed at take-off or landing."