United States Air Force has imposed a restriction on pilots weighing less than 61.7kg/ 136 pounds from flying the F-35A Lightning II. This is due to safety concerns about the ejection process in a portion of the flight envelope.
During tests by Martin-Baker, the manufacturer of the F-35 ejection seat, an unacceptable risk of neck injury was uncovered for the parachute deployment/opening phase for lighter-weight pilots at the low-speed regime. There is also an elevated risk for pilots weighing between 61.7kg to 74.8kg (165lbs). While the odd of an ejection in the low-speed condition is very small, the risk of a critical injury is higher than for older fighter ejection seats. The chance of a serious and potentially fatal neck injury from an ejection in the low-speed flight envelope is one in 50,000 flight hours for pilots under 61.7kg and the probability for those weighing 61.7kg to 74.8kg (165lbs) is one in 200,000.
As an interim solution, pilot weighing less than 136 pounds will not be allowed to fly the F-35 until the problem is resolved. The Air Force has accepted the risk for continuation of flight for pilots weighing within the 136 to 165 pound range. Only one pilot was affected by this restriction. The problem is expected to be resolved in one year with the cost to be paid by Martin-Baker. The solution include installing a switch that would slow the ejection process when lighter pilots are flying, an alteration to the parachute to delay the opening sequence. In addition, the air force is exploring how to reduce the weight of the pilot’s helmet. The Rockwell Collins GEN 3 helmet allows the pilot to see through the cockpit floor by fusing imagery from six infrared camera mounted on the airframe. The helmet currently weighs about 5.4 lbs/ 2.4 kg. Rockwell Collins is working on reducing the weight by 6 lbs / 0.27 kg.
USAF
During tests by Martin-Baker, the manufacturer of the F-35 ejection seat, an unacceptable risk of neck injury was uncovered for the parachute deployment/opening phase for lighter-weight pilots at the low-speed regime. There is also an elevated risk for pilots weighing between 61.7kg to 74.8kg (165lbs). While the odd of an ejection in the low-speed condition is very small, the risk of a critical injury is higher than for older fighter ejection seats. The chance of a serious and potentially fatal neck injury from an ejection in the low-speed flight envelope is one in 50,000 flight hours for pilots under 61.7kg and the probability for those weighing 61.7kg to 74.8kg (165lbs) is one in 200,000.
As an interim solution, pilot weighing less than 136 pounds will not be allowed to fly the F-35 until the problem is resolved. The Air Force has accepted the risk for continuation of flight for pilots weighing within the 136 to 165 pound range. Only one pilot was affected by this restriction. The problem is expected to be resolved in one year with the cost to be paid by Martin-Baker. The solution include installing a switch that would slow the ejection process when lighter pilots are flying, an alteration to the parachute to delay the opening sequence. In addition, the air force is exploring how to reduce the weight of the pilot’s helmet. The Rockwell Collins GEN 3 helmet allows the pilot to see through the cockpit floor by fusing imagery from six infrared camera mounted on the airframe. The helmet currently weighs about 5.4 lbs/ 2.4 kg. Rockwell Collins is working on reducing the weight by 6 lbs / 0.27 kg.
USAF
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