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Head and Neck Protection System for Acute and Chronic Injury Mitigation


OBJECTIVE: Develop prototype systems to mitigate acute head and neck injuries due to high G loading in the ejection environment and mitigate chronic neck fatigue and pain associated with prolonged low G use of Helmet Mounted Display Systems. DESCRIPTION: Advancements in combat aircraft performance and flight equipment design, particularly the widespread use of helmet-mounted display systems (HMDS), have led to an increase in reported neck pain and injury due to G loading among aircrew across all services. While neck pain and injury has long been an established risk with fixed-wing and rotary-wing combat flight, increased use of head/helmet supported masses – from night vision goggles, to Joint Helmet Mounted Cueing System (JHMCS) and Helmet Mounted Inertial Tracker (HMIT) systems deployed in thousands of legacy aircraft, to advanced systems deployed in the HMDS of 4th and 5th Generation Fighter Aircraft – has exacerbated the issue. These helmet-supported masses shift the center of gravity (CG) more forward and superior to the normal CG of the current helmet system. Under rapid high G loading or over prolonged usage in the low G environment, this added weight and adverse CG location both increases the stresses placed the neck and spine at all times during flight operations and increases the risk of cervical spinal injury during ejection. Recent surveys show that over 80% of USAF pilots using such systems report neck fatigue associated chronic neck pain. These issues have the potential to jeopardize mission success and increase potential mishaps as pilots reportedly avoid flying to the aircraft’s full potential in order to lessen their pain. Furthermore, these issues have reduced USAF force readiness, and in some instances, led to pilots seeking medical treatment from providers outside the Department of Defense. The development of an assistive technology to augment the pilot’s ability to manage additional head-mounted mass and adverse CG during both normal maneuvers and ejection scenarios would greatly decrease pilot injury risk, improve force readiness, restore mission performance, and reduce medical treatment costs. Potential solutions should minimally impede a pilot’s head motion and operational Range of Motion (ROM) while inside the aircraft and ideally would be virtually imperceptible to the user, yet provide assistive force when required. Failure to give attention to these concerns has caused previous attempts at a solution to be rejected by the user community. Potential solutions should also give consideration to size, weight, and power (SWaP) constraints present in fixed-wing and rotary-wing aircraft cockpits. The aircrew gender and size demographic is wide ranging, including the 5th percentile female (103 lbs) to 95th percentile male (245 lbs). Proposed solutions should accommodate this wide demographic and be interoperable with aircrew flight equipment (AFE) worn by all sizes of aircrew. PHASE I: For the Phase I effort, contractors shall develop and execute a plan for establishing end user requirements and develop a proof of concept (TRL 2-3) for their proposed system to determine its technical feasibility. Establishing design requirements via engagement with end users is highly recommended for successful user integration. Early coordination with USAF Agile Combat Support Directorate Human Systems Division (AFLCMC/WNU) and other DoD PEOs interested in incorporating this technology into their systems is also recommended. Proofs of concept should demonstrate technical feasibility by delivering a report containing results of benchtop experiments, models and simulations, or calculations that show successful implementation of actuation schemes, control algorithms, developed hardware, and any other vital components of the system. Technical data, including AFE specifications, dangerous/safe neck loading conditions, aircraft information, etc. will be provided to Phase 1 awardees. PHASE II: Contractors awarded a Phase II shall mature their proof-of-concept into a prototype that simulates integration with aircrew flight equipment (AFE) or aircraft system integration (i.e., a reasonable surrogate of AFE or existing aircraft systems such as an ejection seat), and is testable in simulated flight environments with anthropometrically represented manikins (centrifuge, drop towers, and horizontal acceleration sleds). The system should demonstrate a capability for attenuating neck loads by at least 25% compared to an unaided helmet-supported mass in high +Gz testing on AFRL impact facilities with both 5th percentile female Lightest Occupant in Service (LOIS) and 95th percentile male Large Anthropomorphic Research Dummy (LARD) manikins. The system must demonstrate scalable attenuation up to a +12 Gz impulse (simulated ejection scenario) in order to ensure the system can provide adequate neck load protection, without introducing additional injury modes to the user. Prototype systems should also demonstrate they allow users to perform all necessary duty activities with minimal ROM loss and minimal additional effort of motion required. Finally, awardees shall deliver a detailed plan for integrating the system with existing aircraft systems and (AFE). PHASE III DUAL USE APPLICATIONS: Phase III awardees shall build upon their Phase II prototype, such that it furthers the attenuation neck forces and head accelerations to safe levels under operationally relevant test conditions, without introducing additional modes of injury, reducing user ROM, or requiring additional effort of motion in order to complete duty tasks. The Phase III prototype must also demonstrate reasonable success at satisfying critical requirements for adoption, including those required to integrate with aircraft systems and AFE. The conclusion of the Phase III shall deliver a prototype system that demonstrates attenuation of a pilot’s head and neck loads during routine High +Gz exposure, as well as ejection cases, to a Multi-axial Neck Injury Criteria (MANIC) rating of less than 5% injury risk in all three (X, Y, Z) axes (Parr, 2014). The prototype must be shown to be effective while also requiring little, if any, additional effort of motion on part of the user and not restrict user ROM in any way that would preclude them from accomplishing mission-critical tasks. This system would provide tremendous benefit to fixed-wing fighter squadrons that employ helmets equipped with HMDs or similar helmet-supported masses by reducing neck injury risks and will increase force readiness, while decreasing the need for medical rehabilitation. Potential transitions include the relevant fighter, attack and trainer aircraft program management offices of the USAF Life Cycle Management Center and NAVAIR. The system could also similarly benefit the Future Vertical Lift program (minus any components specifically needed for ejection) with similar helmet mounted systems. Additionally, this system could provide a therapeutic rehabilitation tool to medical professionals treating cervical spine injuries or neuromuscular conditions that affect the ability of a person to keep their head upright. REFERENCES: 1. Harrison, M.F., Coffey, B., Albert, W.J., and Fischer, S.L. (2015). “Night vision goggleinduced neck pain in military helicopter aircrew: A literature review.” Aerospace Medicine and Human Performance, 86(1), 46-55. 2. Philip S.E. Farrell et al. (2016) “Aircrew Neck Pain Prevention and Management”. Human Factors & Medicine Panel NATO Research Task Group 252 STO Technical Report. 3. Turner, Anthony M. (2018) “Pilot Questionnaire to Characterize Neck Pain Related to Forward Helmet Center of Gravity (U.S. Air National Guard)”. 711th Human Performance Wing USAF School of Aerospace Medicine. 4. LaFiandra, M. et. al. (July 2007) “The Effects of Personal Armor System for Ground Troops (PASGT) and the Advanced Combat Helmet (ACH) With and Without PVS-14 Night Vision Goggles (NVG) on Neck Biomechanics During Dismounted Soldier Movements”. US Army Medical Research and Materiel Command report. 5. Parr, Jeffrey C., Michael E. Miller, Joseph a. Pellettiere, and Roger a. Erich. 2013. “Neck Injury Criteria Formulation and Injury Risk Curves for the Ejection Environment: A Pilot Study.” Aviation Space and Environmental Medicine 84(12): 1240–48. 6. Parr, J. (2014). "A Method To Develop Neck Injury Criteria To Aid Design And Test Of Escape Systems Incorporating Helmet Mounted Displays." Doctoral Dissertation, Air Force Institute of Technology. Dayton, OH KEYWORDS: neck pain, neck injury, chronic pain, helmet mounted display, aircraft ejection, head injury, head supported mass, ejection injury
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