The F-35 Joint Program Office is about to begin testing a prototype for a new helmet for pilots of the Joint Strike Fighter—a critical upgrade to the aircraft's control systems. The current Generation III helmet, which acts as a heads-up instrumentation and night vision display for the pilot, was discovered last year to be so heavy that it snapped the neck of smaller test dummies during ejection testing.

The Gen III helmet, which is essential to the operation of the F-35 in all its variations, has pushed forward the art of augmented reality. Combined with optic and infrared sensors on the aircraft, it essentially allows the pilot to look through the plane—a feature much desired by the Marine Corps for precision vertical landing of the F-35B. It also allows pilots to track, designate, and fire weapons at targets by looking in their direction—without having to turn the aircraft toward them. But the helmet has encountered multiple growing pains, including problems with image "jitter" early on in testing that could cause pilots with the strongest of stomachs to get motion sickness.

The mass of the approximately 5-pound, $400,000 Gen III helmet could push the pilot's head down during the acceleration of ejection and cause both neck and back injuries to pilots. When combined with the sudden forces exerted by the opening of the ejection seat's parachute, particularly when the seat pitches to the point where it is nearly upside-down when the parachute opens, it could be enough to break the neck of lighter pilots.

As a result, pilots under 136 pounds have been barred since last fall from flying the F-35 Lightning II, and the JPO has acknowledged that pilots between 136 and 165 pounds face an "elevated level of risk" of neck injury.

The new helmet being prepared for testing is 10-percent lighter. The F-35 JPO and Lockheed are also working on making modifications to the ejection system that slow the seat after ejection and a head support panel on the seat itself that prevents neck hyperextension. The goal is to remove size restrictions on pilots for the F-35 by November.