Testers this summer discovered that a lightweight pilot’s neck could snap during a low-speed ejection, with the bulkier helmet like the F-35’s Gen III.
Officials said the risk of neck injury during both phases of an ejection increase, because the forward center of gravity brings the pilot’s head down. However, one expert said that removing helmet weight will not solve the basic problem of “misalignment of the pilot” when the main parachute deploys.
An F-35 hearing is scheduled for next week. Rep. Mike Turner, R-Ohio, told Defense News earlier this month, “I am going to have an oversight hearing on this.”
Military sources told Defense News that, “Testers found the ejection snapped the necks of lighter-weight test mannequins.” The potentially fatal problem did not occur during previous tests with the slightly lighter Gen II helmets, according to the source.
The main physical difference between the helmets is that the Gen III system weighs about six ounces more than the old Gen II helmet. This weight increase is primarily due to improvements to the night-vision camera.
The Joint Program Office initially blamed the jet’s ejection seat for this problem. But interviews conducted by Defense News in recent weeks indicate the added weight and bulk of the new F-35 helmet complicates matters. “It is still unclear whether the blame rests squarely with the helmet, or the seat, or somewhere in between.”
During sled tests with the Gen III helmet in July and August — a 103-pound mannequin at 160 knots, and a 136-pound mannequin at the same speed both failed.
Until a permanent fix is found, the US military services have grounded pilots weighing less than 136 pounds, Defense News first reported Oct. 1.
The restrictions only affect pilots under this threshold because lightweight individuals generally have lower neck strength to absorb force, JPO spokesman Joe DellaVedova said Wednesday.
The services are not placing any flying restrictions on heavier pilots, he added.
During flight tests earlier this year, Lockheed Martin suggested “system workarounds” that could alleviate the problem, for instance adding chin pads. But the JPO decided the best long-term solution was to remove weight from the helmet, officials said.
A preliminary design review on the improved helmet is scheduled for December, DellaVedova said.
Ideas to reduce helmet weight include the reduction of internal strapping material, as well as removing an external visor.